Troubleshoot SAML sign in for Confluence Datacenter

[Portal]

I was handed a windows server 2025 that has JIRA installed and was asked to install Confluence. I'm trying to not go down the same route as the JIRA install with local users and no SSL.  (http://jira.[domain.com]:8080 is base url, whch I hope to fix soon. 

In light of that, I am attempting to set up confluence, with SSL reverse proxy and use M365 as IDP for SAML authentication. 

For confluence: 

• Installed nginx for reverse ssl proxy and added certs
• Installed Postgres 17
• Installed Confluence 10.2 as service
• Setup SCIM/user mapping (groups and users sync)

SSL is all working fine, but I'm having trouble with SAML user authentication.

In 365, I have an Entra enterprise app that shows success for the login, The confluence app attempts to login and then shows

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URL: https://confluence.[domain.com]/plugins/servlet/sam|consumer

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"Oops and error has occurred"

Cause

Exception Request Unique ID: 15acec1c-0d1f-4399-ba25-437707fbfd2b

Referer URL

https://login.microsoftonline.us/

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Hoping someone has a good method of diagnosing this. I wasn't able to figure out exactly where to look for the log of the error.

Forgive my ignorance, but what other support avenues are available for on-prem installs? AI and knowledge base information was helping, and hoping this guides me, but ultimately may need direct human support. 

Thanks!

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