2025: macOS Server 5.6.3 - Apple Push Notifications (APN) - Renew... error: "An unexpected error (-80010) has occurred."

It's that time of year again, where I have to spend hours trying to keep my macOS Server configuration working for the next year due to the annual APN certificate expiration.

I encountered this same error last fall, but was ultimately able to renew my certificate on 11/25/2024 with an expiration date of 11/25/2025.

This year, I've had no luck getting past this error. I'm using LetsEncrypt for all of my other certificates on this server, except for APN, which I understand has to come from Apple, and cannot be replaced with a third party certificate.

On the Apple Push Certificates Portal there is no option under "Certificates for OS X Server" but Revoke. There is an option to Create a Certificate for Third-Party Servers, but I'm not aware of a way to use those with macOS Server (would be great if someone could find a way).

I take it from this earlier thread that nobody ever found a solution or workaround for this other than giving up on push notifications altogether and resorting to polling? Moving away from my decade-old macOS Server setup is not a viable option for me right now.

(BTW, If anyone wonders how this is even still working, it's in a macOS 10.13.6 VM running under Parallels on a 2018 Mac mini presently running macOS 15.7.2; years ago I migrated my old physical server configuration into the VM).