Is it still possible to upload avatars?

I set my forum avatar sometime last year without a single problem.

Now no matter what I try to change it to it seems I always get 'invalid file'. The .jpg is 80x80, under the 39KB filesize limit and isn't saved with any kind of weird compression etc.
Tried both files from my PC and from a link.

Is a forum plugin malfunctioning or something, preventing the upload of avatars or is it just somehow me?

 

Contacted.