@lyse@lyse.isobeef.org Changing the user name helped, it now says Authenticated to git.mills.io ([199.247.16.95]:2222) using "publickey". ssh-add ... had no effect (even after ssh-add -D).
Here’s a debug log, @prologic@twtxt.net, perhaps you could take a look at this 🙏: https://movq.de/v/116c5f514b/clone2.txt
(Might be a silly mistake on my part. Wrong remote path or something?)