Admin Console Log in failed!

I forgot to mention I am using a mac

After having installed couchbase I accessed the Admin Console. After a page refresh I was asked to insert Username and Password. I input the details I has set at installation time. I get the message

Log In failed. Try again.

This has happened to me before. At the time I reinstalled Couchbase was able to access the Admin Console Again, but the same thing happened again.

Any ideas on what might be causing this?