We cannot reproduce it - not on any other device, and not on any of our other members on production... He isn't doing anything different than we always do when making a call, so I don't have any steps to reproduce that I can try. I'll wait for it to reproduce on that specific member's device and have him send the logs.

Thanks for the quick reply! It does seem like a timeout after giving up, we don't see logs from provider(_:perform:) when this reproduces. The app does some UI work on the main thread when starting a call, but it is all done pretty quickly (and we never experienced a case where the UI was blocked even briefly during this phase), and this user doesn't have a problem closing the call screen when he sees it doesn't connect. The app is not suspended when the bug reproduces - the user remains on the foreground, waiting for it to connect. I will pass the sysdiagnose instructions to the user and reply here with the results - hopefully it will answer all these questions. Thanks!

Same here - everything is setup according to the documentation, the push is sent, but never received.