"site admin" section is missing after upgrade

I run G2 on my main domain and also a sub-domain. I upgraded the sub-domain to 2.1.1 and the main domain is still at 2.0.2. All was working until I did this. At this time I can still do everything on the main site (2.0.2) and the site admin section will come up but the site admin section on the sub-domain (2.1.1) will not come up like it use to.
I have completed a remove and reinstall of the sub-domain but it still does not work.

Any help please.