Describe the bug When initiating an audio call - this fails. Receiving one works fine. Initiating a video call works fine.

To Reproduce Steps to reproduce the behavior:

1. Go to 'Chat-Window of a user who is capable of A/V calls'
2. Click on 'phone handset' to initiate an audio call
3. See error: call failed

Expected behavior The call should be established the same way as an incoming audio-call or video-calls (they work both ways) in general.

Screenshots i might add later if needed.

Details (please complete the following information):

• Siskin Version: [e.g. 6.2(1)]
• iOS 12.4.9
• iPhone 5s

Additional context