for me , i was getting erroe loading dependencies / error loading layout/ 500 internal server error by updating dash and related libraries has solved the problem
previous:
loguru

pymongo

pandas

dash==2.15.0

dash-bootstrap-components==1.5.0

sqlalchemy==1.4.17

openpyxl

dash-ag-grid

python-dotenv

updated to:

loguru==0.7.3

pymongo==4.10.1

pandas==2.0.3

dash==3.0.3

dash-bootstrap-components==1.6.0

dash_mantine_components==0.12.1

sqlalchemy==2.0.40

openpyxl==3.1.5

dash-ag-grid==31.3.1

python-dotenv==1.0.1

Flask==3.0.0

dash-extensions==1.0.15

plotly==6.0.1

dash-daq==0.6.0

requests==2.22.0

numpy==1.24.4

Werkzeug==3.0.1

dash-table==5.0.0