I can see messages in the logs of forum.friendi.ca:

2026-07-31T04:55:01Z app [NOTICE]: Invalid HTTP signature, message will not be trusted. {"uid":0,"actor":"https://friendica-sverige.se/profile/leanderlindahl", ... ...

At a first glances I can tell that your server is communication via IPv6 with forum.friendi.ca. But there is no AAAA DNS record for your IPv6 (2a01:4f9:c015:6d88::1).

root@forum:~# host friendica-sverige.se
friendica-sverige.se has address 65.109.12.183
friendica-sverige.se mail is handled by 0 mail.friendica-sverige.se.

I'm nor sure if this causing the messages about an invalid HTTP signature Friendica is reporting. But you should repair this nonetheless.