I have just pushed an update of the packages that now include 5.25.5, which is the current “Extended Support Release” of Mattermost. Please be aware that this will very likely be the last update to these packages.
Could this be the problem why websockets are not working?
Do you mean: “It does not work simply because it shows a different name for the issuer”? If so then, no I don’t think so.
But the issuer name implies that at your company a custom ca is installed on workstations. This can be used to decrypt traffic. And maybe the system that decrypts traffic also mangles it and breaks the websocket connection.
Again: I would recommend to follow up with the it responsible at your company because this cannot be meaningfully debugged without access to the environment or knowledge about configuration/product details only your it knows.
Any other Idea or input what I can do to either get it straight up running, or get you more/correct informations so you might identify the problem?
When I last debugged this error message it was caused by Mattermost not being able to connect to kwmserver. So I would make sure that kwmserver is running and that Mattermost has access to it as well as that clients will be able to access it (reverse proxy setup for external access).
If this is a commercial deployment you could also get in touch with our sales team at info at kopano dot com to organise a remote session on your system.
the webmeetings plugin and meet are two separate pieces of software, which at the moment do not interact (and only relate to each other because they are webrtc based and use kwmserver as a signalling server).
That Mattermost sometimes does not load after enabling the plugin is known, but since there are not that many users using it we did have a priority for fixing this. Honestly there is even a chance that the plugin will be discontinued and be replaced with a simple wrapper around Meet.
We have a pr ready that implements OpenID connect (as for example provided through Kopano Konnect). We still need some more votes on the feature request to convince the Mattermost team that the community wants it. Please feel free to share the link ;-)