Redirecting to localhost after login.

[errorr404]

After login it is redirecting to localhost:8080, not to the base URL.

[DivyanshBatham]

Even after adding new Client Id and Secret with the new callback - https://cb-imgur.netlify.com/auth_cb

There seems to be some kind of error:

Back to our site is taking back to https://cb-imgur.netlify.com

[DivyanshBatham]

Got it, the issue is that:
Whenever the user visits an internal links (which are handled by react router) directly i.e. fresh load, netlify tries to find a file named like that.

For example:
https://cb-imgur.netlify.com <- This will send back the index.html
https://cb-imgur.netlify.com/something <- This will send back a 404, since there is no file named something.html on the server.
But if you go to the first link, and then navigate to something, then that will get handled by react-router.

[DivyanshBatham]

Fix: Add a netlify.toml file with the following snippet of code:

[[redirects]]
  from = "/*"
  to = "/index.html"
  status = 200

Ref. - https://www.netlify.com/docs/netlify-toml-reference/