My mail app does not work

I have tried countless times to set up all my mail in my mail app with no results. I have tried to add my yahoo(ymail) and my Google(gmail) and even my iCloud to my email app on my iPhone6. Every time it comes up with connection server error.

I have deleted these accounts and tried to add them again with no results. I have tried setting them up manually with no luck either.

Not sure what to do anymore except use multiple mail apps on my iPhone6 which is a pain (I know first world problems!!)