A Hop reader may go offline temporarily (that is, it’s not connected to our server for a brief period due to a connection problem, power outage or maintenance), during which time it won’t display details about your time remaining and amount charged. Instead, it will simply show a green check-mark and “Welcome aboard!” Your tap transaction will be processed shortly as soon as the reader re-connects to the server. Some riders who get a pass from their work or school (to which expiration times do not apply) will also see “Welcome aboard” when they tap.