How can I submit a calling or debug report?

After the issue has occurred: 

In the conversation list:

1. Tap your Profile in the upper left corner.
2. Tap  Settings.
3. Tap Advanced.
4. Tap Submit debug/calling report.

Please describe briefly what went wrong to help us to identify the issue.

Calling logs do not include: any call content, personal information, fingerprint, device ID, user ID, or IP address.