When the auto-login attribute is set to true on certain [MM_..._Link] SmartTags, a login token is created that allows the customer to be automatically logged in when they click the link. The auto-login link sent to the customer will only be valid for a specific period of time. The default lifespan is 15 days but this value can be changed on General Settings > Other Settings > Login Token Settings.

If multiple auto-login links are requested by the same user within a 24-hour period, they will all use the same login token.