Similar to this issue Can't setup Discourse ID: Application with this redirect URI already exists My self-hosted Discourse has this exact error. But the thread above was already closed and didn’t see the answer on how to fix, but happy that issue was resolved. Is it possible to help my forum as well? Ready to share the URL in PM if it’s ok

This should be resolved via PM now. The original issue was that this instance was registered a while ago, the server has issues, so the site manager had to reinstall Discourse and the credentials didn’t carry over.

Please share the URL via PM, thanks.

I’m having this exact same issue. Can I PM you as well? EDIT: nevermind I fixed it myself :slight_smile:

Could you share, how did you carry over the credentials? So that I could also do it myself in the future without bothering the Support?

The problem was with the domain, so I switched to a subdomain and it fixed it.

Hi there, I am having the same issue. I had to create a fresh install and now am getting this when trying to enable the discourse id login. I am guessing due to briefly creating an install before with the discourse id login enabled. I had to destroy that instance and install a new one. Is there a way to resolve this?

Send me a PM with your site’s domain name and I’ll help you resolve this issue. Sorry about this, we’re working on a more straightforward solution.

For future travellers, we have updated Discourse to handle this issue. The issues describes here shouldn’t happen going forward, ID will be able to generate new keys if the same redirect uri is used for a new registration.

Can't setup Discourse ID: redirect URI already exists

Product Support

Czar (Czar) February 15, 2026, 6:22pm 3

It seems that I don’t have PM permissions yet as a new user, it’s my first time interacting with Discourse. Could you PM me please, if it’s possible?

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Can't setup Discourse ID: redirect URI already exists

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