Avatars don't show for users with "special" characters in their username

Hey,

Just recently the avatars of some users on my forum stopped working. I haven't added any hacks or even edited anything on the forum recently, and this is what some of the users' avatars are showing as:



And even if they try to change their avatar in the control panel, it won't let them.



But when I look in the admin panel, I can see their avatar:



My Profile.

Does anyone know what the problem could be and how I can fix this? I also tried clearing the cache, but no luck :(

Thanks

EDIT: It looks like this problem only occurs to the users who have "special" characters in their username on my forum.

Hello Danny ,

You can include userid to your avatar rewrite rules. It will auto fix the problem

Thanks a lot Mert.

It worked

You're welcome