iTunes sign in

Itunes wont let me sign in,

I sign in with correct email/password and it accepts it but then asks me to sign in again straight away. Cant access anything on the app and I've reset my password 3-4 times now with no success. Been going on for a while now but ignored it as I don't usually use the app but now it's starting to irritate me a tad...

Any solutions would be appreciated :)

Freddie