Does it instantly fail or do the first two progress blocks turn green but the third one ultimately turns red?
I would say about 90% of the time it turns red instantly, and then 10% of the time it hits the first two blocks green and then fails.
Please check server task log > Sub tasks for detailed logs in ePO console.
Or navigate to server.log file in ePO installation directory under logs folder which will be having detailed error codes.
Try re-deploying the agent with the 'forceinstall' switch on a sample from the 90% and see if that helps.
For the 10%, confirm that task actually fails on some of the targets. Often the task succeeds but there was a communication problem preventing the agent from telling the ePO server that it succeeded.