Hi @subee.admin
The guides appear to use opaque access tokens which are not in JWT format (I wouldn’t have thought these were readable on jwt.io) unless you have a custom API defined in your Auth0 dashboard with an identifier that you’re using as an audience value in your app, this will produce a token in JWT format (see https://auth0.com/docs/security/tokens/access-tokens). If so, I would just ensure the identifier of this custom API and your audience value match exactly. If you were using the {YOUR_AUTH0_DOMAIN}/userinfo as the audience value then your access token will be an opaque string.
For more information about creating and configuring an API in Auth0, see: https://auth0.com/docs/apis
Otherwise, did you notice if there was anything off on jwt.io? access token expired perhaps?
I would also check the OIDC Conformant switch, located in the client’s advanced settings. See this for more info: https://auth0.com/docs/api-auth/tutorials/adoption/oidc-conformant
Regards
Saqib.