Hi Narendra,
You can check a few things:
1. Check how many configurations exist by clicking on Select configuration option, maybe there is no config that exists and you are trying to edit null and hence the error.
2. Try creating a new configuration.
3. If you still have auth issues, immediately after clicking on edit when you get the authorization error, go to transaction SU53 to see the auth object that failed. You would then need to reach out to your Basis team or whoever created your user to grant you the corresponding authorizations.
Hope this helps.
Regards,
Parul