Donations not working

We have “Email Access” enabled at the global level. We also have “Guest Donations” enabled under the individual form settings, as well as the “Registration” option set to “None”. However, when I go to make a donation on this page:

https://thegoodfightfoundation.org/offerings

It says, “Error: You must log in or create an account to purchase a subscription”

If I uncheck “Make this donation recurring for 12 months”, it then throws a different error:

It says, “Error: The merchant login ID or password is invalid or the account is inactive.”

Please help! This is very frustrating. I have followed all documentation and instructions.

The page I need help with: [log in to see the link]