What is DCDIAG you ask?
This command-line tool analyzes the state of one or all domain controllers in a forest and reports any problems to assist in troubleshooting. DCDiag.exe consists of a variety of tests that can be run individually or as part of a suite to verify domain controller health.
Let’s get back to clearing the errors, one might say that this is a difficult task. Not so much.
Just open up Eventvwr and clear the logs, re-run dcdiag and the errors should go away.
You could also try running dcdiag /fix to let it apply safe fixes.
For a full list of dcdiag commands, go here.