Returns the activated user.

The given userId corresponds to a deleted user. Recreate the user first (using POST /api/v2/users) and then activate it.

The given access token is either missing, invalid, has expired, or has been revoked.

The given access token does not have the required OAuth scope to execute the request.

The given userId does not correspond to any existing user.

The client has sent too many requests in a short amount of time.