Error establishing a database connection

Question

I have a Wordpress app on Azure App Service. It is linked with an Azure Database for MySQL flexible server. The database server seems down at the moment, and when I access the wpdbserver configuration page in my Azure Resource Group, only three dots are spinning forever. How can I fix this? How do I add a firewall to limit connection to internal WP app, and also add a firewall to my wordpress app to only allow traffic from Cloudflare?

It's my first time working with Azure App Service

Thanks very much for your help, guys!