- please post screen with list all VMware services with "Log On As" column...
- which database are you using?
- which account is configured to access this database?
- are you using self-signed certificates?
Also check these KBs (not all directly for 5.5. anyway check them):
VMware KB: Alerts are displayed in vCenter service status after upgrading to vCenter Server 5.x
Thanks,
P.