UpdateAsync throws "User with old email does not exist in Auth0 database"

I am trying to update a user in a custom database to mark them has verified.

When I try to call the update I received this error message:

“User with old email does not exist in Auth0 database”

My code looks like this;

var request = new UserUpdateRequest()
            {
                EmailVerified = update.EmailVerified,
                Connection = _managementClient.Connection,
                
            };


            var user = await _managementClient.Client.Users.UpdateAsync(id, request, cancellationToken);

   

What is causing this error message? I am not changing the email address and the user still exists in the Auth0 admin portal.

what is the resolution of this error?
i am also facing this issue in simple update of email to a user in Auth0 standard database.

{
“statusCode”: 400,
“error”: “Bad Request”,
“message”: “User with old email does not exist in Auth0 database”,
“errorCode”: “auth0_idp_error”
}
curl command
curl -H “Authorization: Bearer eyJ*zI5Q" -X PATCH -H “Content-Type: application/json” -d '{“email”:"M@GMAIL.COM”,“connection”:“axa-ktaxa-b2b”}’ https://xxx.au.auth0.com/api/v2/users/auth0|ssss*************cc