Azure App service connect to SQL Server on premise without hybrid connection

I have a Web API deployed to an Azure service app (2 nodes). I want to connect to an on-premise SQL Server 2016 database.

I get the message:

Cannot connect to the database

I disabled the firewall on the on-premise SQL Server (to test), but it still is not working.

I can connect running the app on my PC connecting to the SQL Server (by ipnr), but not if I publish it to Azure (I checked the web.config in Azure, it is looking good). I am using an ipnr (in the connection string) to connect.

• .NET framework 4.5.2
• Entity Framework 4.6.3

It's already working with a hybrid connection, but that's limited to 25 connections, in my case, the app will be used by a lot of concurrent users, like 200 users, so I don't want a hybrid connection. I want a direct connection based on an ipnr and firewall settings. Or another solution.

Hybrid connection is working, but is limited to 25 connections. I have more concurrent users.

It must connect with the on-premise SQL Server database.