Let's Encrypt on 3CX Domain: How does it work?

[LuckyDuckemz]

3CX Version: 16.0.3.676 with 3CX Provided Domain
Server OS: Windows Server 2016 Standard
Is the 3CX Server Hosted and where? Internal
IP Phone Make/Model/Firmware: Yealink T48S 66.83.0.20
Provisioning Method: Local
Trunk Provider or Gateway Make/Model: Century Link
Has the Firewall Checker passed: NO
Are custom Phone Templates being used: YES

Issue: SSL Cert Renewal is failing
Error Message: SSL Certificate renewal has been failed. Error: SSL certificate failed due to network conditions. Unable to reach Certificate Issuing Servers. The process to renew your certificate will start again in a couple of hours.

Does the 3CX Provided Domain using Let's Encrypt behave like an automated cerbot installation? That is-- does the 3CX web host send out a renewal request and Let's Encrypt expects to be able to reach the host at all times on 80/443?

Trying to find out if there is anything specific to allow through the firewall and if there have been any changes to manually initiate a cert renewal.
Also wondering if passing Firewall Checker ensures SSL can be renewed, too. Thanks!

 

[Saqqara]

I would check your dns settings, and make sure their are point to google 8.8.8.8 and 8.8.4.4