Keep clicking Retry.  That is a SQL lock... using the Sage credentials, so I'd suspect something like Sage Intelligence or BI dashboard.

Make sure no one else is posting or has a GL report open.

Thanks BigLoue.. the issue resolved itself, Controller tried again later in the day and he was able to close GL. So there was probably a lock as you mentioned and whatever process was locking it freed it up.. Thanks again 

Lots of times the CFO or Controller will keep opening GL reports and leaving them open which will result in this message.