Azure App service connect to sql server on premise without hybrid connection

I have a webapi deployed to an Azure service app (2 nodes). I want to connect with a on premise sql server database (2016).

I get the message: "cannot connect to the database". I disabled the firewall on the (on premise) sql server (to test). But still not working.

I can connect running the app on my pc connecting with the sql server (by ipnr), but not if I publish it to azure. (I check the web.config in azure, looking good). I am using an ipnr (in the connection string) to connect.

.net framework 4.5.2 entity framework 4.6.3

(its already working with a hybrid connection, but thats limited to 25 connections, in my case, the app will be used by a lot of concurrent users, like 200 users), so I dont 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 sql server database.