I recently updated all of servers with iDRAC6 modules from firmware version 1.99 to 2.80 as some of them became un-reachable and required a reset. After completing this I found when launching the console I would get the following error after Java loaded up:
Login failed, possibly due to slow network connection. Please try again.
I did find a thread that indicated deselecting Video Encryption fixed the issue for others in the past, however this did not work.
I did discover that this issue only occures when I login with AD creds, i.e. Microsoft Active Directory. If I use the local root creds the console launches without issue.
I have verified that this functioned on the previous firmware version 1.99.