I've successfully been able to get the OAuth2 plugin registered and configured to the point it asks me to authenticate the mailbox. However, once I authenticate and accept the App permissions, it redirects me back to my osTicket instance and 404s.
My web app redirect URI is https://IP-Address/api/auth/oauth2
I'm still using the local IP instead of a domain because I'm trying to make sure everything works before I do domain cutover, since this is a migrated system.
I know I have to use either http://localhost/ or https in Azure, and I got around that by issuing a certificate to the new instance using letsencrypt. I would think if it was an SSL issue on the redirect from Azure, it would just show the normal HTTPS Certificate Invalid warning in my browser, instead of a 404.
I feel like I've hit a dead end. Any assistance is appreciated.