>> Can you check the certificates' serial numbers? >> The working one begins with 03 and the problematic one with 04. >> >> There are 37 archived certificates for this hostname, 29 begin >> with "03" and only 8 with "04". >> >> Certificates starting with "04" occur since autumn 2019. >> After that date it's sometimes "03" and sometimes "04". > > This looks exceedingly unlikely to be relevant.
Very far-fetched, I thought something might be cached or pinned. And as supposed this is not relevant, I tested it and a "04" certificate worked well. Best regards Gerald
