Q. Why I can not drag cell contents in Excel sheet?

I have come across with similar problem many times in the past and for some reason I can't remember how to solve this problem. This time when I was working on data creation using Excel, the same problem occurs.

I tried searching on the web but didn't find even a single site where there is a reason mentioned clearly about why all of a sudden this happens.

Why this option gets disabled automatically in excel sheet ? Anyone of you know the reason this WHY then please share it...!

When we try to access any of the available DCRM organization on DCRM 2011, and if you see any of the below errors indicate that a key is not being regenerated correctly.  

Error message in Event Logs: Current key (KeyType : CrmWRPCTokenKey) is expired. This can indicate that a key is not being regenerated correctly.  

Error message while accessing Microsoft Dynamics CRM GUI: