All participants can't hear or see each other in the beginning of the meeting

Using the web external_api.jsi and server domain: meet.jit.si:
It sometimes takes a few seconds up to a few minutes for a meeting to fully function. Initially, everyone (2-5 people) has blank thumbnails and everyone’s audio and video show as muted in the thumbnails event hough everyone actually has unmuted video and audio buttons. It can stay in this state for up to a few minutes then suddenly, everyone’s audio and video starts working.

Somewhat related: after someone leaves a meeting it takes up to a minute for their blank thumbnail to fully disappear.

I’m guessing the bug is on the server because sometimes everything works perfectly even though no front end code is changed.

Does anyone know what might be causing this problem?

Thanks