Hi @TaaviE
one label may have max. 63 characters, so that label is ok.
But there is an additional limit: The CN can have (if I know it correct) max. 64 characters. Yours has 66.
You may add a second, shorter domain with that domain as first domain name -> so it's used as CN.
Earlier, I've created a certificate with this-is-a-very-long-really-very-long-name-of-this-small-bdomain
as subdomain name (63 characters + .server-daten.de
). Worked with www.server-daten.de
as second domain name and CN.
Ah - there is the old topic