@Greenreader9 thank you, I could indeed re-create another account immediately when the “borken” one was deactivated.
I got most of it working, but I can’t seem to install the certificate I received earlier today (before the account recreation) for this domain. Does it need to be re-created? Domain name is identical.
Note: It’s not that I can upload the certificate but it isn’t trusted. It just doesn’t get assigned at all. I simply uploaded the private key and then the certificate, incl. the opening “-----” comments. I’ve tried with and without a closing CR/LF. I still get ERR_SSL_PROTOCOL_ERROR on the client.