My bike is not moving in the Zwift app on my iPhone 8 app

I’ve been on Zwift for 4 weeks now and for the past two attempted rides I have had problems. The bike showed it was riding but the wattage was off the charts at 1,200? Today my bike is not moving? I am all paired up and it should be working. Any recommendations? I am trying a new blue trainer tire but I cannot imagine that would be the problem.