When creating a New Certificate - Generate Let's Encrypt Certificate and filling out the necessary information the process times out. Identical errors in the GUI and CLI. The corporate FQDN being used for this certificate has a "-" in the middle of the address.
Firewall settings on the corporate firewall, settings inside FreePBX were all verified that Port 80 was selected and forwarded to the internal IP of the PBX.
I have another domain, without a "-" in the middle, that I created a new A-record for and pointed it to my static corporate IP address. No other changes were made to firewall settings on the corporate side or the FreePBX side. Only setting that was updated in FreePBX was the Hostname was updated to match the new A-record created above.
Certificate was issued within seconds.