ITunes Match wont authorise on a new PC running Windows 10

Hi I bought a new pc running Windows 10 last weekend. I've installed the most up to date version of iTunes, authorised it etc and I can see and play all my music that I have put in the Cloud, but I cannot 'Switch iTunes Match on. I go to the link, the tiny link on the iTunes store and it takes me to the iTunes Match screen with two options. 'No Thanks' and 'Authorise this Computer' (specifically for ITunes Match). I click on that and it requests that I put in my Apple ID and password, it thinks about it for a second, goes back to the iTunes Match login screen then just hangs.

I've tried it multiple times and always the same thing. Any ideas gratefully received?

Regards,

Rog