I’m using the multipage with the Multiplexer extension.
Converting a project to be compatible with the Multiplexer requires an alternative import and some changes to the app-statement.
In absence of a minimal working example, your code should look something like this:
from dash_extensions.enrich import Output, DashProxy, Input, MultiplexerTransform, html, State
....
app = DashProxy(
__name__, plugins=[dl.plugins.pages],
external_stylesheets=[dbc.themes.FLATLY],
server=server,
transforms=[MultiplexerTransform()],
suppress_callback_exceptions=True
)