I have had these issue several times and would like to post this on my blog hoping this will be useful for someone.
When trying to logon to the SAP Crystal Report Enterprise it connects fine but when I try to retrieve a universe a message pops up which is attached to this blog, which reads as
"Please check your logon credentials and make sure your network is properly configured before trying again. If the problem persists please contact your Administrator"
The issue was with a version mis match. Crystal Report Enterprise was on 4.2 SP3 and the platform version is on 4.2 SP4. The way you can check is in the SAP Crystal Reports for Enterprise window click Help --> About SAP Crystal Reports for Enterprise.
After upgrading the SAP CRE to 4.2 SP4 it works fine.