The error message you are seeing suggests that the file located at the path “file://C:\xampp\htdocs\Projectname\storage\oauth-private.key” either does not exist or is not readable by the application or user attempting to access it.

Here are some steps you can take to troubleshoot this issue:

1. Verify that the file actually exists at the specified path. You can do this by navigating to the directory in your file explorer and checking for the file.
2. Ensure that the file has the appropriate file permissions set for the user or application that needs to access it. You may need to change the file permissions to allow read access to the appropriate user or application.
3. Check that the path is correctly specified in the code or configuration file. Ensure that there are no typos or errors in the path, and that any backslashes are properly escaped.
4. If you’re running a web server, make sure that the user that the web server is running as has permission to access the file. This may require changing the user or group ownership of the file.
5. If you’re still having trouble, you may need to regenerate the private key file or obtain a new one from the relevant OAuth provider, depending on the specifics of your use case.

In my case. I have passport:install issue

Only you have to run this command in your terminal

php artisan passport:install