Cannot add collabolator to repository

As mentioned in the topic, I cannot add a new collaborator to the existing repository. I tried to create a new repository, the result was the same. After typing the username or email list with users to choose does not show. I tried all of this combination on chrome, firefox, and mobile browser. All of the attempts failed. Please fix the bug.

See this post, same problem:

if you join an existing thread your chances of finding a solution are higher, since you might discuss the issue with other uses who are experiencing the same problem, and because older posts are more likely to receive staff support first.

I’ve a similar problema today (checked with other developer)
if i try to add a collaborator to my repo, his name will be resolved as usercode and not accepted…