I have tried to follow your instructions which ahs been fine up until the last step.
Under the "Instagram Account" heading, click the 'Instagram Login' link and authorize Easy Instagram to access your account by entering your Instagram username and password. This process should return you back to the Easy Instagram Settings page in your WordPress CMS, where you will see your Instagram User ID.
I click the "Instagram Account" heading, authorise my site to access Instagram but then instead of taking me back to the settings page I get returned to the front end home page. When I go into the WP back end and visit the Easy Instagram settings page again there is no account there.
I look forward to your reply,