Hi, been in touch with shopify they have advised it should be fixed now!

Hi, Yes I am getting this with out store too, we've had customers calling and when we try it ourselves we also get the same! Ive looked at a couple of other shopify stores and they seem to be doing it too! Hopefully we get an answer soon.

Hi, is anyone else getting an issue where you go to check out and you get redirected to the home page again? Checked a few other stores I know using shopify and some of those are doing it too!

Yeah same message received here. I use 123reg.