Video and audio lags for 5-10mins for some clients in UAE

Hi,

We setup coTURN server to relay traffic for clients in UAE since the default TURN server did not work for their networks. Everything now works fine but for certain clients, we see a lag or a distortion of video from time to time. We have attached a screenshot of what it looks like. What could be the reason for this?

Regards,
Team Telzee