So trying to check our UCS server I ran into this issue today.
If you aren't running the latest UCS software then certain versions of Java will toss this error. If you need to get logged in and don't have the option for updating the UCS software right away then here's how you can get around it.
Just enable HTTP via SSH and you can then login. Remember to disable this once you have your UCS software and Java versions current because until you do everything is transmitted in clear text.
UCS# scope system
UCS /system# scope services
UCS /system/services# enable http
UCS /system/services# disable http-redirect
Warning: When committed, this closes all web sessions
UCS /system/services# commit
Once this is done now you can connect to the UCS Manager without the error.