Error: Connection closed by remote host. Is borg working on the server?

[s-fischbach]

Hi!
I use Vorta with borgbase and have made several dozens of backups to my repository so far. A few days ago (might be related to updating from Fedora 42 to 43?) my remote backups started failing (not local ones).

Vorta states: "Error: Connection closed by remote host. Is borg working on the server?"

Vorta log:

2025-11-13 12:04:17,242 - vorta.borg.borg_job - WARNING - Remote: ** WARNING: connection is not using a post-quantum key exchange algorithm.
2025-11-13 12:04:17,243 - vorta.borg.borg_job - WARNING - Remote: ** This session may be vulnerable to "store now, decrypt later" attacks.
2025-11-13 12:04:17,244 - vorta.borg.borg_job - WARNING - Remote: ** The server may need to be upgraded. See https://openssh.com/pq.html
2025-11-13 12:04:17,437 - vorta.borg.borg_job - WARNING - Remote: ssh_askpass: exec(/usr/bin/ksshaskpass): No such file or directory
2025-11-13 12:04:17,439 - vorta.borg.borg_job - WARNING - Remote: abc@abc.repo.borgbase.com: Permission denied (publickey,gssapi-keyex,gssapi-with-mic).
2025-11-13 12:04:17,448 - vorta.borg.borg_job - ERROR - Connection closed by remote host. Is borg working on the server?

(repo URL modified)

I read the FAQ and checked steps 1 to 6. I was unsure how to check step 3 (key encryption), but I've never been prompted for a password so far when using Vorta, so I guess it's not encrypted. With step 6, I get a "PTY allocation request failed on channel 0" and the FAQ states "then the login step still worked.". Okay, but my backup does not. Do you have any advice on how to proceed? I'm a bit lost...

Thanks a lot in advanced
Sebastian