To make sure you have full access to your Paperless Forms data for your connectors without any issues, you can whitelist the following address:
paperlessbi.mysql.database.azure.com:3306
Otherwise, if you wish to be more precise, you can add these addresses to your firewall:
40.69.104.0/27
40.69.105.0/27
40.86.226.166/32
40.86.226.230/32
52.229.122.195/32
52.229.123.147/32
52.229.124.23/32
52.242.26.53/32
52.242.29.91/32
52.242.30.154/32
52.242.36.107/32