What is the difference between an expired, inactive or a cancelled member?

A cancelled member is one that has cancelled their membership in the 'Your Account' page (Department) or you have manually cancelled their membership in 'Edit Member Details'.

A cancelled member continues to have access to your site up until the new renewal date. That is because they have purchased a certain amount of time on your site that they are still entitled to. They will then be set to "inactive" and not be able to login anymore.

If don't want a member to have access to your site, (such as a refund request) then set their status to inactive.

An expired member is one that has an expiration date attached to their membership that has lapsed without them renewing their membership. Expired members are not able to login until they renew.