Lets Encrypt - The previous attempt to enable Let’s Encrypt failed

When turning on Lets Encrypt I receive the following error on only one of my UTMS.

 

The previous attempt to enable Let’s Encrypt failed: Registration with the Let’s Encrypt server failed. Please try again later or see the Let’s Encrypt website for possible causes.

 

Of course the link just takes me to the Lets Encrypt home page instead of anything actually helpful. What processes does the UTM take to register for Let's Encrypt? I need some basic trouble shooting ideas as I see absolutely nothing in the logs.