I can't for the life of me get an app inventor app to place a phone call. Is this feature broken on certain phones or versions of Andriod?
The same thing is happening to me; the app would just refuse to place a call. There was no error. I've given phone permissions and I'm on the latest version of android.
The phone in specific is a OnePlus Nord.
Why don't you try call Phone.MakePhoneCallDirect? Notice the "Direct" at the end? It bypasses having you to go to the phone app to make it. This worked for me.