My ipad stopped allowing me to sign on as host.

Hi, @KathyDC,

Are you logged in to the Zoom application?  Click the Join button for the meeting in your list of meetings and it should start.  If not, there's not much information here to help you with... please provide additional detail, or submit a Support Ticket:

Support Ticket entry: https://support.zoom.us/hc/en-us/requests/new

If you are not logged into the account on your iPad, you should log in to the Zoom web portal on your browser:

https://zoom.us/signin 

... and try starting the meeting from your list of meetings in the web portal:

https://zoom.us/meeting#/upcoming 

If this doesn't work... is this a meeting that you created, or someone else?  If someone else, you should check with them to make sure the link you have is complete.

Hopefully something here helps!