When a member's account is marked as expired or canceled, their access to restricted content is revoked. For expired members, access is revoked immediately. For canceled members, their access is revoked once the expiration date on their account is reached.
Members with expired and canceled accounts will still be permitted to log into their accounts, they simply won't be allowed to access any content.
Permitting expired and canceled members to log in is necessary so that they may renew their membership if they so choose.