you are missing the required support template. Please fill this form out and edit into your post. This will give us the technical info and logs needed to help you in case the machine in question in spitting out errors! Since you’ve provided zero technical details it is impossible to help you as-is. Thanks.
indicates you are not using valid public certificate.
such thing does not exist. Either it is self-signed or it comes from letsencrypt
Collabora integration might help with troubleshooting. But I would focus on the self-signed problem first.