Raid bar disappear

So first of all,sorry for my poor English as English was not my first language.Im facing the problem about the raid bar disappear.me and my friend has build a raid farm above the sea level.When we get the bad omen,we went to the platform that suppose for the monster drop.So me and my friend has tested for a few time,when we get the bad omen,the bar will load but at the end it will disappear!please helpppp