I setup a first repository on local disk, it went fine. Next I tried setting up repo on my nas to clone the files. I installed git-annex on the NAS (it's armel arch) and created the repository via webapp, I entered the password once. Git-annex started syncing the remote repo and after few seconds password pop-up hell broke loose. I was flooded with password-prompt pop-up windows. The synchronization was continuing regardless of correctly/incorrectly entered passwords. What's more, these popups grab the keyboard and you cannot do (appropriate word) with your system.
I checked this topic: http://git-annex.branchable.com/forum/ssh_password/ and ssh config is in place on my computer and on the NAS.
What is causing this and how can I get rid of this?