Interactive phone call push notification stopped working - only works in xcode

Hey, i have an app with a notification action that enables the user to make a phone call directly from the notification. I made this a good while ago, but we just noticed that it stopped working everywhere - except for when i install it via xcode.

To make a long story short, what i do is that in didReceiveNotificationResponse, i get the phone number out from the payload and finally i call

[application openURL:[NSURL URLWithString:[@"tel://+" stringByAppendingString:msisdn]] options:@{} completionHandler:nil];

This used to result in that the dialog pops up from the bottom with the phone number and a "call" button, but now it works when installed from xcode, but nothing happens when installed from testflight.

I have made debug traces and it gets to the openurl-row with the correct phone number, but nothing seems to happen when i call it.

Any idea what has changed? I made this several years ago and haven't touched the code. Pointers appreciated!