A Channel in Iguana refers to a specific interface that is configured. In order for the interface to work, the channel must be running. Sometimes, a channel may stop. In this case, a user at the practice that has been provided with a login to Iguana must start the channel back up.
Please follow the link to the Iguana Support Site. This link will provide step by step documentation on starting or stopping channels in Iguana: https://help.interfaceware.com/v6/starting-and-stopping-channels