Unauthorised WOPI-Host (Comodo PositivSSL Mulit Domain Certificates)

Does someone else use a Comodo PositiveSSL certificate for the nextcloud server host and the collabora online server?
When I use my Comodo PositiveSSL Multi Domain certiicate, i get the “unauthorised WOPI-Host” message.
When I replace the Comodo PositivSSL Multi Domain certificate with a self signed certificate (Self Root CA is added to the Nextcloud rootcerts.crt and the Nextcloud ca-bundle.crt) everything works fine.

I cannot find a solution for using my Comodo certificates.

Kind Regards, Roland

Are you using the Docker container?

No! I use the debian 9 packages from collabora.

Kind regards, Roland