I can't get a certificate


I cant get a SLL Certificate for the domain “ktb.selfhost.eu”!
Can i delete older ones to get a new one
What can i do?


No, there’s nothing you can do except wait. Unfortunately, the other users of selfhost.eu have used up all of the Let’s Encrypt rate limit for that domain:

Rate Limit Current Status Domain
50 Certificates per Registered Domain per week Limit exceeded (52/50 this week). Next certificate issuable at 2018-12-31T20:12:22.000Z. selfhost.eu

Summary generated at https://tools.letsdebug.net/cert-search?m=domain&q=ktb.selfhost.eu&d=168 .

You should either get the owner of selfhost.eu to apply to the Public Suffix List, or use a different shared domain that is already on the PSL: https://publicsuffix.org/list/public_suffix_list.dat