Meet - could not connect to server - check internet connection

we are faced with a problem with kopano-meet. Since the SSL Certificate CA Issue of Letsencrypt our kopano-meet (via UCS) does not work.

We can login normally (SSO), but are unable to use it for videoconferencing.

Only error we get in the preview-window “could not connect to server - check internet connection”.

So we reached out to our support-company. They told us, that the issue is caused by the above mentioned Letsencrypt - CA in connection with the turnserver of kopano-meet and that there is no solution for this problem at the moment.

I am wondering whether no kopano-meet installation is working on the whole world when using the kopano-turn-server?

Have you any hints about that? Are you also facing the problem?

Thanks a lot!


sorry, I thought that Kopano-Meet in connection with UCS is “some kind of different” to Kopano-Meet “without” UCS.

Just updated the UCS Server (with Meet) to 4.4-8 errata1067 and updated all packages except the OpenID Connect Provider: Version 1.0-konnect-0.23.3 (cause 2.0 is making troubles, we were told).

The problem persists.

Turn-Server is:

It seems like you all don’t have this problem?

Is this issue related to the turn server of kopano we use?

I don’t use Kopano, but there were issues with the LE cert and in another thread on this forum there was a workaround posted with a manual edit to the problematic cert. As far as I know this issue has not been corrected with a UCS update yet. I have no info on whether or not UCS is working on it, but the work around fixed the issue I was having with a different application that used a LE issued cert.

Try a search for system diagnostic invalid certificate and see if that thread helps.


do you mean this one: System diagnostic suddenly gives me: Found invalid certificate '/etc/univention/letsencrypt/signed_chain.crt'

Yes. The marked solution is what I did on my server. After replacing the cert manually I was able to get the browser to connect successfully.

I think we are talking about different problems. I try to explain the problem again.

We are able to log in to kopano-meet. We also can create a call. But we are unable to start the call cause we get a red message at the top of the kopano-meet window in the browser which says "Failed to connect to server. Check your internet connection. This message appears as soon as kopano-meet opens.

It looks like this


Beside of that we are not having the directory “letsencrypt” on our UCS installation. (the path which is mentioned in the linked thread does not exist)