I had the same error and it stems from the api key and settings not saving. You can manually set the data in the db but you’ll need to change this to suit your install
INSERT INTO `user_settings` (`user_id`, `locale`, `setting_name`, `assoc_type`, `assoc_id`, `setting_value`, `setting_type`)
VALUES ('1', '', 'apiKeyEnabled', '0', '0', 'a:1:{s:5:"en_US";s:1:"1";}', 'object');
INSERT INTO `user_settings` (`user_id`, `locale`, `setting_name`, `assoc_type`, `assoc_id`, `setting_value`, `setting_type`)
VALUES ('1', '', 'apiKey', '0', '0', '[your key displayed on the profile API page]', 'string');