I had a free 3 month certificate with 4 separate domains, all running on the same server (Synology virtual servers), without a problem. All domain names would lead to a seperate website and all would have https automatically without a problem, using the same certificate, because all domains would point to the same public fixed IP address. The certificate was previously issued through the Synology interface.
It did not automatically renew for some reason, like it used to before, probably because the internet provider decided to change my fixed IPv4 address when introducing IPv6 a month ago. Maybe some temporary mismatch in the DNS entries of said 4 domains caused this.
The certificate expired on 14 jan 2021 and I have not been able to get a new free 3 month multi domain certificate since. I have been able to get a free 3 month SINGLE domain certificate through Synologies interface, so communication with Let's Encrypts server works and authentication for one domain works too.
Working with certbot is a bridge too fare as yet, for me . , it appears...
Why can I not enter multiple domains, like www.domain1.com;www.domain2.com;www.domain3.com;www.domain4.com any more
in the SAN field? (See pic attached). It currently will not accept anything there...
I know I should ask Synology also, but maybe there is a restriction from Let's Encrypt?
What can I do to get the certificate with 4 domains back?