Authentication can fail even when the login system itself is working.
One common reason is an incorrect redirect URL.
What Is a Redirect?
After authentication, the provider needs to know where the user should return.
For example:
Login
↓
Authentication Provider
↓
https://example.com/auth/callback
Local Development
During development, you may use:
http://localhost:3000
Production normally uses HTTPS and a real domain.
Configure Both Environments
Keep development and production URLs clearly separated.
Development
localhost
Production
example.com
Common Problems
Typical mistakes include:
- Wrong protocol
- Wrong domain
- Wrong callback path
- Missing production URL
- Old deployment URL
- Incorrect trailing path
Test After Deployment
Do not assume configuration is correct because local login works.
Open the production website and test:
Signup
Login
Logout
OAuth
Password reset
Custom Domains
If you change the application's domain later, review redirect configuration again.
For example:
old-domain.com
↓
new-domain.com
Authentication settings may need updating.
Final Thoughts
Redirect configuration is a small detail that can have a big effect on authentication.
Treat production URLs as part of your deployment checklist.