Not active oauth tokens after reboot

The oauth code in APM has mechanisms for syncing the token DB over to an HA peer, so it should survive a failover.

If the tokens aren't being generated with the right dates, then nothing will work right. I'd begin troubleshooting that before anything else because it's fairly basic. It seems unlikely that APM OAuth AS is completely broken with the default or default-ish settings. Can you share information about the "long lifetime" set up in your oauth profile so we can try it in a basic lab setup?