Retry
The payment is attempted again on the method already on file, after the number of days you set. Nothing changes for the member yet.
Grace
A grace window opens and the member is notified. Access continues, because a card that expired is not the same thing as a member who left.
Suspend
The membership suspends and access pauses. How much survives the suspension is a setting, not a rule the software imposes on you.
Cancel
The membership cancels after the escalation window you set, and what it was worth stays counted as revenue recovered or lost.