Hi Denish,
In the log file you shared you can see the login_required error returned. This is a normal error that occurs when the user is not logged in with Auth0.
Silent authentication works by making a request to Auth0 in the background. If the user has logged in previously, Auth0 will use their session to issue a new token without prompting the user to enter their credentials.
The session expires after a certain period of inactivity (meaning no interaction with Auth0) as well as after a certain time period regardless of activity. You can configure the expiry times with the Inactivity timeout and Require login after settings respectively as explained here: Configure Session Lifetime Settings
You should handle the login_required (and other error responses) by redirecting the user to the universal login page without prompt=none in the URL parameters.
Please read through the following article. It will help you understand the error responses from silent authentication in more detail: Configure Silent Authentication