@PeterT94 Can you start with the below 5 steps? Let me know if none of them resolve the issue by replying to this message and we can assist you further.
Check the logs: Check the logs for your Azure App Service and Azure Database for MySQL flexible server to see if there are any error messages or warnings that could indicate the cause of the issue.
- Check the VNet integration: Verify that the VNet integration between your Azure App Service and Azure Database for MySQL flexible server is configured correctly. Ensure that the VNet and subnet are correctly configured, and that the private DNS zone is correctly set up.
Check the firewall rules: Verify that the firewall rules for your Azure Database for MySQL flexible server are correctly configured to allow traffic from the VNet.
Check the connection string: Verify that the connection string for your Azure App Service is correctly configured to use the private DNS zone and VNet integration.
Check the service endpoint: Verify that the service endpoint for your Azure Database for MySQL flexible server is correctly configured to allow traffic from the VNet.