Apple TV app won't work on Macbook Air

Recently signed up for a subscription to Apple TV again - it works on the app on my iphone; but whenever I try to watch something on my laptop - the app opens, I can select the show I want - then it opens a black screen for about 5 seconds; then closes it and takes me back to the homepage of the app. My macbook is up to date with updates; I've cleared the cache; I've restarted it, etc. No idea what is going wrong as everything else on the laptop works with no problems!!! Obviously some sort of glitch with the app software, no idea what to do.