Indeed a nice suggestion to really strip the problem to the minimum!
I put the code into my run.py, and again, I get “Hello world” at 127.0.0.1:5000, and I get the following error when accessing the website from another machine (I get briefly “Loading…” and then a blank page):
Error: Minified Redux error #14; visit https://redux.js.org/Errors?code=14 for the full message or use the non-minified dev environment for full errors.
Ui https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
r https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
r https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
p https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
_n https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
Ds https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
Bh https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:126
Dj https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:162
unstable_runWithPriority https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:25
Da https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:60
xb https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:162
Bj https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:162
U https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:16
onmessage https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:24
EventHandlerNonNull* https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:24
<anonymous> https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:9
<anonymous> https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:9
react-dom@16.v2_10_2m1730126952.14.0.min.js:125:24
Me https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:125
callback https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:138
Wg https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:67
oj https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:127
Aj https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:160
unstable_runWithPriority https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:25
Da https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:60
ab https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:154
Te https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:146
Pg https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:61
unstable_runWithPriority https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:25
Da https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:60
Pg https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:61
ha https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:60
Dj https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:163
unstable_runWithPriority https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:25
Da https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:60
xb https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:162
Bj https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:162
U https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:16
onmessage https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:24
(Async: EventHandlerNonNull)
<anonymous> https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:24
<anonymous> https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:9
<anonymous> https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:9
Uncaught Error: Minified Redux error #14; visit https://redux.js.org/Errors?code=14 for the full message or use the non-minified dev environment for full errors.
Ui https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
r https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
r https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
p https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
_n https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
Ds https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
Bh https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:126
Dj https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:162
unstable_runWithPriority https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:25
Da https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:60
xb https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:162
Bj https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:162
U https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:16
onmessage https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:24
EventHandlerNonNull* https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:24
<anonymous> https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:9
<anonymous> https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:9
dash_renderer.v2_10_2m1730126951.min.js:2:106040
Ui https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
r https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
r https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
p https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
_n https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
Ds https://xxxxxxx.xxx/_dash-component-suites/dash/dash-renderer/build/dash_renderer.v2_10_2m1730126951.min.js:2
Bh https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:126
Dj https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:162
unstable_runWithPriority https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:25
Da https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:60
xb https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:162
Bj https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react-dom@16.v2_10_2m1730126952.14.0.min.js:162
U https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:16
onmessage https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:24
(Async: EventHandlerNonNull)
<anonymous> https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:24
<anonymous> https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:9
<anonymous> https://xxxxxxx.xxx/_dash-component-suites/dash/deps/react@16.v2_10_2m1730126952.14.0.min.js:9
From here it shall be possible to track what is not working. To get a clearer look at what is happening, I modified slightly the code to this version:
import dash
dashApp = dash.Dash(__name__, serve_locally=True)
dashApp.enable_dev_tools(debug=True, dev_tools_ui=True, dev_tools_hot_reload=False, dev_tools_serve_dev_bundles=True)
app = dashApp.server
dashApp.layout = dash.html.Div("Hello world")
The error is a bit more clear:
Uncaught Error: When called with an action of type "SET_LAYOUT", the slice reducer for key "layout" returned undefined. To ignore an action, you must explicitly return the previous state. If you want this reducer to hold no value, you can return null instead of undefined.
combination Redux
recordHistory reducer.js:88
reloaderReducer reducer.js:121
Redux 2
storeEffect React
commitHookEffectListMount react-dom@16.v2_10_2m1730126952.14.0.js:19866
commitPassiveHookEffects react-dom@16.v2_10_2m1730126952.14.0.js:19904
callCallback react-dom@16.v2_10_2m1730126952.14.0.js:182
invokeGuardedCallbackDev react-dom@16.v2_10_2m1730126952.14.0.js:231
invokeGuardedCallback react-dom@16.v2_10_2m1730126952.14.0.js:286
flushPassiveEffectsImpl react-dom@16.v2_10_2m1730126952.14.0.js:22988
unstable_runWithPriority react@16.v2_10_2m1730126952.14.0.js:2685
runWithPriority$1 react-dom@16.v2_10_2m1730126952.14.0.js:11174
flushPassiveEffects react-dom@16.v2_10_2m1730126952.14.0.js:22955
performSyncWorkOnRoot react-dom@16.v2_10_2m1730126952.14.0.js:21872
flushSyncCallbackQueueImpl react-dom@16.v2_10_2m1730126952.14.0.js:11224
unstable_runWithPriority react@16.v2_10_2m1730126952.14.0.js:2685
runWithPriority$1 react-dom@16.v2_10_2m1730126952.14.0.js:11174
flushSyncCallbackQueueImpl react-dom@16.v2_10_2m1730126952.14.0.js:11219
flushSyncCallbackQueue react-dom@16.v2_10_2m1730126952.14.0.js:11207
batchedUpdates$1 react-dom@16.v2_10_2m1730126952.14.0.js:21997
Redux 6
_callee$ api.js:122
tryCatch api.js:2
makeInvokeMethod api.js:2
defineIteratorMethods api.js:2
asyncGeneratorStep api.js:2
_next api.js:2
promise callback*asyncGeneratorStep api.js:2
_next api.js:2
_asyncToGenerator api.js:2
_asyncToGenerator api.js:2
apiThunk api.js:133
middleware Redux
storeEffect React
commitHookEffectListMount react-dom@16.v2_10_2m1730126952.14.0.js:19866
commitPassiveHookEffects react-dom@16.v2_10_2m1730126952.14.0.js:19904
callCallback react-dom@16.v2_10_2m1730126952.14.0.js:182
invokeGuardedCallbackDev react-dom@16.v2_10_2m1730126952.14.0.js:231
invokeGuardedCallback react-dom@16.v2_10_2m1730126952.14.0.js:286
flushPassiveEffectsImpl react-dom@16.v2_10_2m1730126952.14.0.js:22988
unstable_runWithPriority react@16.v2_10_2m1730126952.14.0.js:2685
runWithPriority$1 react-dom@16.v2_10_2m1730126952.14.0.js:11174
flushPassiveEffects react-dom@16.v2_10_2m1730126952.14.0.js:22955
commitBeforeMutationEffects react-dom@16.v2_10_2m1730126952.14.0.js:22834
workLoop react@16.v2_10_2m1730126952.14.0.js:2629
flushWork react@16.v2_10_2m1730126952.14.0.js:2584
performWorkUntilDeadline react@16.v2_10_2m1730126952.14.0.js:2196
EventHandlerNonNull* react@16.v2_10_2m1730126952.14.0.js:2219
<anonymous> react@16.v2_10_2m1730126952.14.0.js:15
<anonymous> react@16.v2_10_2m1730126952.14.0.js:16
redux.js:564
The above error occurred in the <UnconnectedContainer> component:
in UnconnectedContainer (created by Connect(UnconnectedContainer))
in Connect(UnconnectedContainer) (created by UnconnectedAppContainer)
in UnconnectedAppContainer (created by Connect(UnconnectedAppContainer))
in Connect(UnconnectedAppContainer) (created by AppProvider)
in Provider (created by AppProvider)
in AppProvider
Consider adding an error boundary to your tree to customize error handling behavior.
Visit https://fb.me/react-error-boundaries to learn more about error boundaries. react-dom@16.v2_10_2m1730126952.14.0.js:19662:15
Error: When called with an action of type "SET_LAYOUT", the slice reducer for key "layout" returned undefined. To ignore an action, you must explicitly return the previous state. If you want this reducer to hold no value, you can return null instead of undefined.
combination Redux
recordHistory reducer.js:88
reloaderReducer reducer.js:121
Redux 2
storeEffect React
commitHookEffectListMount react-dom@16.v2_10_2m1730126952.14.0.js:19866
commitPassiveHookEffects react-dom@16.v2_10_2m1730126952.14.0.js:19904
callCallback react-dom@16.v2_10_2m1730126952.14.0.js:182
invokeGuardedCallbackDev react-dom@16.v2_10_2m1730126952.14.0.js:231
invokeGuardedCallback react-dom@16.v2_10_2m1730126952.14.0.js:286
flushPassiveEffectsImpl react-dom@16.v2_10_2m1730126952.14.0.js:22988
unstable_runWithPriority react@16.v2_10_2m1730126952.14.0.js:2685
runWithPriority$1 react-dom@16.v2_10_2m1730126952.14.0.js:11174
flushPassiveEffects react-dom@16.v2_10_2m1730126952.14.0.js:22955
performSyncWorkOnRoot react-dom@16.v2_10_2m1730126952.14.0.js:21872
flushSyncCallbackQueueImpl react-dom@16.v2_10_2m1730126952.14.0.js:11224
unstable_runWithPriority react@16.v2_10_2m1730126952.14.0.js:2685
runWithPriority$1 react-dom@16.v2_10_2m1730126952.14.0.js:11174
flushSyncCallbackQueueImpl react-dom@16.v2_10_2m1730126952.14.0.js:11219
flushSyncCallbackQueue react-dom@16.v2_10_2m1730126952.14.0.js:11207
batchedUpdates$1 react-dom@16.v2_10_2m1730126952.14.0.js:21997
Redux 6
_callee$ api.js:122
tryCatch api.js:2
makeInvokeMethod api.js:2
defineIteratorMethods api.js:2
asyncGeneratorStep api.js:2
_next api.js:2
promise callback*asyncGeneratorStep api.js:2
_next api.js:2
_asyncToGenerator api.js:2
_asyncToGenerator api.js:2
apiThunk api.js:133
middleware Redux
storeEffect React
commitHookEffectListMount react-dom@16.v2_10_2m1730126952.14.0.js:19866
commitPassiveHookEffects react-dom@16.v2_10_2m1730126952.14.0.js:19904
callCallback react-dom@16.v2_10_2m1730126952.14.0.js:182
invokeGuardedCallbackDev react-dom@16.v2_10_2m1730126952.14.0.js:231
invokeGuardedCallback react-dom@16.v2_10_2m1730126952.14.0.js:286
flushPassiveEffectsImpl react-dom@16.v2_10_2m1730126952.14.0.js:22988
unstable_runWithPriority react@16.v2_10_2m1730126952.14.0.js:2685
runWithPriority$1 react-dom@16.v2_10_2m1730126952.14.0.js:11174
flushPassiveEffects react-dom@16.v2_10_2m1730126952.14.0.js:22955
commitBeforeMutationEffects react-dom@16.v2_10_2m1730126952.14.0.js:22834
workLoop react@16.v2_10_2m1730126952.14.0.js:2629
flushWork react@16.v2_10_2m1730126952.14.0.js:2584
performWorkUntilDeadline react@16.v2_10_2m1730126952.14.0.js:2196
EventHandlerNonNull* react@16.v2_10_2m1730126952.14.0.js:2219
<anonymous> react@16.v2_10_2m1730126952.14.0.js:15
<anonymous> react@16.v2_10_2m1730126952.14.0.js:16
error.js:16:20
Now I shall try to understand what is the problem, but I do not know hot to debug in the browser and pinpoint clearly what is going on. Any other suggestion? Thank you!