Important topic!!! Expiring certificates are a know issue. There is a hidden article in the subscriber portal by Bill Turner from Support. In addition the "CreateOAuthCertificate" fix is literally placed next to every installation package on the Aras FTP, but people hardly notice it.
We even have this forum solution, which helped many people back then, but today it’s not as well-known anymore: How to update expire Aras certifies | Aras
The solution shown was one of the most-liked posts in this forum´s history, highlighting just how desperate people were to resolve this issue
I am surprised that you got "Authentication errors on sign-in"! From my experience this issue mainly affected the file vault. And I am even more surprised you needed multiple attempts with support. Has the behavior of expired certificates changed in the latest versions?
I like your solution with the installer. Seems much more easier than doing the manual certification. I always needed a few attempts to create working certificates. Most important tip for everyone: Use plenty of calendar reminders so you don't forget to rebuild the certificates before they expire. :)
I assume we’ll start seeing this issue more often soon, because I14 users mainly perform patch upgrades instead of the full upgrades we had when moving from I12 to I14. Fun times ahead!