Checkout page will not load when using stealth redirect code (2nd post)

I redirected from my primary domain to an addon domain using stealth redirect code. I am inexperienced building websites but have learnt a lot of the last year. I bought a domain that I could not match the social media too so I hoped to have address this by redirecting the site i have built to a new domain name. Everything seemed fine until I tested the shop, I can see the shop and add to basket but then the checkout simply won’t load using the button or right clicking and opening in a new window. I deleted the redirect code and now the shop works fine, but on the primary domain, the domain name that I don’t want to use for my site. I am looking other options for redirecting that will not affect woo commerce or a workaround using the redirect code. Any help, suggestions or comments gratefully received!

Fortyeights.co.uk / forty8s.com