Video stopps after few seconds

BLIZZ company version.
WIN 10, connected DSL to router by ethernet, no WLAN.

We broadcast our church services via BLIZZ. In the beginning it went very well.
For a few weeks now, the video image keeps breaking off suddenly and you have to switch the camera on again (in Blizz) after a few seconds.
Depending on the situation, it takes a few seconds to minutes until the image is gone again. After a waiting period of a few 10 seconds, you can switch on the video image in Blizz again.

What can be the reason? We have already exchanged a few components of the transmission path, but without success.

We made a new WIN10 installation on the laptop to prevent, that "old" programs makes trouble.

I have the impression that the error does not occur as long as there are no participants in the meeting. But as soon as there are participants in the meeting, this error occurs.

Can you help me?