Current Problem
When a JIRA user is created with username: Марат, then, although he can can access most JIRA options BUT he can not access Agile Boards.

Reproduce steps
1. On User Management page, create a JIRA user with below username

Марат

2. Log in jira with this username, then go to Agile -> Manage Boards
3. JIRA keep loading the board repeatedly.

Cause
The last character, which is т is an Russian character.

Expected Outcome
This user should access Agile Board without any issue.