Do you have a TV package with Mediacom that includes HISTORY? A re-authentication error usually appears because you've signed in with a Mediacom account, but your service only includes internet (or your TV package doesn't include HISTORY).
You'll need the channel included in your TV package to watch locked programming.
If you don't have a TV package, please disconnect your Mediacom account to see unlocked programming.
For more information, see: I don't have a TV package. Can I subscribe directly to HISTORY?