OAUTH_APPROVAL_ERROR_GENERIC : An unexpected error has occured during authentication. Please try again. Exception in Salesforce

To resolve the "OAUTH_APPROVAL_ERROR_GENERIC : An unexpected error has occured during authentication. Please try again." Exception in Salesforce, please check the following steps.

1. Set Relax IP restrictions in the Connected App and check whether it is because of IP Restrictions.

2. The issue might be due to Scope parameter also. So, adjust it and check.

Note:
For each and every change, Log out, clear Cache and try again.