UserAgent: Mozilla/5.0 (X11; CrOS x86_64 11151.59.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.94 Safari/537.36
Platform: https://training.sportsdata.ag/app/softphone/?&webRTCHostname=webrtc.welzl.org&matchId=802217&phone=447548641003

Steps to reproduce the problem:
1. tried disabling SIP ALG
2. tried various browsers on different devices
3. tried wireshark but can't identify anything, apart from constant 'keep alive' messages and 

What is the expected behavior?
For the softphone not to drop out and reconnect every 15-20 minutes

What went wrong?
The softphone has always worked in the past. It is a browser based one on link - https://training.sportsdata.ag/app/softphone/?&webRTCHostname=webrtc.welzl.org&matchId=802217&phone=447548641003 - but suddenly stopped working

Did this work before? Yes 

Chrome version: 71.0.3578.94  Channel: n/a
OS Version: 11151.59.1
Flash Version: latest

Please help, i am no expert just want this softphone to work on my laptop