I've had this problem for ages with Wingate,
The symptom: All video streaming sites that use RTMP or RTSP, or whatever it's called to play video streams are unable to play videos from any client computers that connect to the internet trough wingate. If I try the same site on the wingate PC thus bypassing wingate it always works.
I've had this issue since I first started using Wingate almost 10 years ago. But enough is enough. I find a solution now, or I have to stop using wingate as a router.