The login method is by using your Instagram account
Go to Privacy and Security on your Instagram account settings and make sure "Private Account" is unchecked.
Your Instagram account should be "Public" otherwise IG Hoot's tools will not work on your account.
If you've already made your account Public then you don't need to follow the step again. You can continue to login from below.
Important! You've to follow all the above steps carefully to use IG Hoot without any issues.