Moved to VSE forum as better place
Moved to ePO to see if that gets a faster response.
How many systems? If just one, have you done an uninstall/reinstall of the Agent?
Are you running distributed repositories? Are they synchronized with the master? Do you have McAfeeHttp configured as a fallback repository?
If the communication is proper and the DAT is not being updated there is a issue with VSE and DAT.
if the DAT version is 1111.0 on client machine for sure the DAT is corrupted.
download the 8xxx.exe from the below site and executed it manually. Then it will update automatically.