WordPress + Okta plugin

I’m trying integrate a dev WordPress instance using the Okta plugin at https://wordpress.org/plugins/wp-okta-authentication/

I get either HTTP 500 error – “Cannot create a user with an empty login name.”

Then OKTA comes back with:
Identity Provider: Unknown
Error Code: invalid_client
Description: Invalid value for ‘client_id’ parameter.


Notice Undefined index: user_pass in /wp-includes/user.php on line 1459
Catchable fatal error: Object of class stdClass could not be converted to string in /wp-includes/formatting.php on line 4669

Seemed the plugin was dropping some data, but after making the config static, I’m getting a better result - portal always says the auth was successful, but the redirect doesn’t appear to be handled properly. Has anyone else tried this particular integration?