User ID is blank in the SAPLOGONTICKET

Hello All,

I'm dealing with a very strange issue of SSO between Portal (SP11) and R/3 system. Everything was working fine and we had to restart the Portal system for some reason. After the Portal restart, SSO stopped working. Now i have configured everything again but still with no luck. I'm getting an error message "Name OR password not found" I went to SM50 and took a trace and found out that User ID is blank there.

Any ideas what could be wrong here.

Regards

Vaib