I'm trying to use Mail on my iPhone.

I'm trying to use Mail on my iPhone. It says "Welcome to Mail" and below that it shows iCloud, Microsoft Exchange, Google and others.

I have an iCloud account but when I enter my email and password it tells me that it is already registered but I still don't get access to any emails as the screen then reverts to showing iCloud, Microsoft Exchange, etc.

Any suggestions would be appreciated.

For some reason I don't have this problem on either of my iPads.