After logging in to a WINXP computer attached to a domain, I get a second login box for Zenworks Configuration Management Login Box.

Unable to login. Error: Unable to log into the network because the login credentials or the server certificate is incorrect.
(Have researched this on this forum - tried several items, but still not working)
Clicking cancel gets by the problem.
Bringing up the Zenworks icon, it shows Logged in as: Not Logged In.

Right Clicking on the zicon, and changing the realm to ZENworkszone allows me to login with no password.

I think the problem is with the certificate.
Going into Configuration, User Sources, status is: Communication with LDAP directory successful.
In the Source, edit connection details, no certificate show up. Click OK, get error: Failed to retrieve the SSL certificate.
Not using SSL, using port 389.

Do I need the certificate - is this causing the problem? Or what is causing the problem?