For *anyone* having issues with domain certificates, please, switch to Let's Encrypt and then report back if that improved the behavior.
Just providing feedback as requested.
We tried Let's Encrypt early on with this current problem.
However, we provide every client with a permanent secondary server access method via a subdomain on a reserved domain of our own. Clients can use that method of access prior to redelegation and in various emergency situations such as where their domains are expired etc.
Over all our servers, that results in thousands of certificates required which include the same root domain name. Let's Encrypt limit requests to 50 per single domain per week as per...
https://letsencrypt.org/docs/rate-limits/
So after issuing certificates for 50 of our clients, Let's Encrypt then refused all further certificate requests over every one of our servers.
We submitted an exemption request to Let's Encrypt for our alias domain, but that wasn't a fast process.
While waiting for Let's Encrypt to process our exemption, we scripted automatic retries to run whenever Sectigo posts a "cannot currently accept incoming requests" error in the logs.
We now operate adequately with Sectigo and all certificate requests are accepted within a few minutes at worst. Our Let's Encrypt exemption has come through since then, but we're now fine with Sectigo. We ran a test run on one server with Let's Encrypt, and it was also fine with the exemption in place.
It would be nice if cPanel could provide the same simple retry logic for Sectigo within their own code for the benefit of all users.
Best regards,
LBJ
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EDIT - Additional...
I've previously provided a basic example of code to handle retries at...
https://forums.cpanel.net/threads/t...-accept-incoming-requests.694129/post-2948185
You can modify that basic example to only run for one user, or even to simply run on the last log with a "cannot currently accept incoming requests" error recorded inside it.