iPad email " this message has not been downloaded...

I have an iPad retina updated to latest iOS. Since ios9 my email sometimes gets an error " this message has not been downloaded from the server". When I first open the email on my iPad I read it fine as it is all downloaded. If I go to my regular PC and delete the message and then go back to my iPad to open it again I get the error. It is a Verizon pop email account. I have it set to delete from server on my Windows Live mail but this never happened before. Before once I opened it on my iPad it stayed with all data even if I later opened same message in my Live Mail account and deleted it. Any idea in settings to fix this. Thanks