Hi @sree1,
Welcome to the Auth0 Community!
It seems that the error you experienced indicates that your Client Secret is not a string, buffer, or KeyObject.
I have just followed the installation steps outlined in here and managed to configure it successfully.
Seeing you still experienced the same error even when using the Auth0 development keys, could you please share the Auth0 Log of the failed login event?
Thank you,
Rueben