What version are you running? 18.104.22.168 What's the URL of the page containing the problem? admin/db/scmtools/repository/add/ What steps will reproduce the problem? 1. Create a repository with a custom bug tracker. 2. Set the URL to http://XXX%20XXX/BID=%d 3. Save the repository. 4. Try create a new review and add to it a BUG id. 5. Save the new review and try to edit it again. What is the expected output? What do you see instead? Cant get to the review edit page, get's an error screen instead. What operating system are you using? What browser? Server: Linux, Client: WindowsXP/Chrome browser Please provide any additional information below. The problem is that the bug tracker URL is not according to python string format. When I changed it to http://XXX%%20XXX/BID=%d everything worked fine. I think you should add a verification check in the repository settings page to make sure that the URL entered is valid (i.e. try to use it to create a URL string). If the URL is not working (i.e. python throws exception) then catch the exception and display the python string formatting rules or provide a link to a page with the formatting rules. In any case it should not cause the review edit page not to come up.