Linphone in iPhone 6+ no stable video-calls between Linux<->iPhone

[Quix0r]

My girlfriend has this device:

iPhone 6+ Software: 12.3 Firmware: 7.80.04

I use Debian Linux at home and I have no trouble at all doing video calls to Android, Windows (not Windows mobile tried yet) or other Linux box. But with her iPhone only encrypted audio calls go through, videos calls open sometimes but only for a second and then we just see ourselfs in the little preview.

I have uploaded a logfile (anonymized her number and name) on my server: https://cloud.mxchange.org/index.php/s/public?path=%2FLinphone

And Linphone seem to sometimes destroys its own data files so she had to reinstall it. Which is annoying, too.

Please investigate.

[Quix0r]

My girlfriend's messages are shown 9 hours from the future while they are correct there. And my messages are shown correctly here but there 9 hours from the past. Maybe that's the issue here? How can we fix this? I never had this with Android or any other non-iPhone user.