Was it online this morning or had it been offline? If it was online this morning and suddenly disappeared from the listing, then my guess is the local feed provider made the decision to discontinue the feed and notified Broadcastify administration of the decision.
If a feed has been offline for 21 days, then it automatically gets deleted. In those cases, the feed provider may have decided to stop providing the feed and just let the feed expire, or there may have been a problem with equipment that couldn't be resolved.