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Error loading dependencies/layout or Server Error 500

Hello, I have a small application. The app read data from Firestore of Google and it is deployed in the App Engine of Google.
Locally runned app works fine, but when i deploy app to App Engine and I try connect to the web page I can see some errors but just sometimes.

In App Engine I use standard mode, I just rewrited example “Hello World” with my app and I added some packages to requirements.txt.

When I run app in flex mode of App Engine, looks that it works fine.

Can someone help me?