Learn how to get your session key.
Make sure you are familiar with the rules before importing.

Your session key is used to scrape paid posts from your feed. After downloading missing posts, the key is immediately discarded and never stored.
Please note that Fanbox and SubscribeStar are in experimental states, and may not work exactly as expected. You are encouraged to report issues with them.
If you're having trouble with the importer, contact admin.