For what it’s worth, I was running into the issue of the same message within WP-Cron Events but instead with a 404 “not found” code…it’s hunting for the file http://yourdomain.com/wp-cron.php. My issue turned out to be an improper file permission on my wp-cron.php file (644 instead of 666) which caused the wp-cron.php file to give the 404… Fixed the permissions and now the warning is gone. This file gives a 200 code now, and cron jobs finally started to run again.
Maybe the 401 that you are receiving is caused by permissions issues on this file as well?