Symptoms

1. JIRA 5.0.2 was recently installed, or your existing JIRA was upgraded to 5.0.2
2. You are attempting to commit a change to your baseURL setting in the General Configuration page and receiving a You must set a valid base URL message
   1. Any domain name that ends with a .colo, .loc, .local, or any other TLD that is not defined will fall prey to this bug.

Cause

The field checker for that field has a constraint that is too tight, as reported in  JRA-27777 - Getting issue details... STATUS .

Workaround

Currently, the only known workaround is to declare your Base URL using the dotted quad octet, i.e. http://10.11.12.13:8080/