Users in the Support category are reporting the error “redirect URI already exists” when attempting to set up Discourse ID. Czar noted a similar closed thread but sought help for their self-hosted instance. pmusaraj requested the URL via private message to investigate. Czar explained they lacked PM permissions as a new user, but pmusaraj confirmed the issue was resolved after PM; the root cause was a server reinstall that failed to carry over credentials. Luna_Mora initially reported the same issue but resolved it independently by switching to a subdomain Czar asked for details on this fix. MadGoose also faced the problem after a fresh install and was directed to PM pmusaraj for assistance. Finally, pmusaraj announced that Discourse has been updated to automatically handle this scenario by generating new keys if the same redirect URI is reused.
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
Please share the URL via PM, thanks.
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?
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.
I’m having this exact same issue. Can I PM you as well?
EDIT: nevermind I fixed it myself 
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.