If you get the following screen back, in a nut shell the HMRC servers were not happy, and as such simply refused to accept your Vat Submission.
Depending on the actual error message shown, depends on if you should try again in 20 minutes.
If you believe your data to be correct and cant get the submission to go through please ring support on 0151 909 5695 or 0161 660 1366.