Cannot access BritBox on my ipad. Subscribed today via the Apple TV app. I get an error message when I try to watch a program that the program is not available in the country that I’m in.

To answer your question:

if you are in a region that offers Britbox, you have an active subscription and can’t access content from the AppleTV application as a channel try downloading the application.

Access it through there.

if that doesn’t work, we will need more information on what happens when you try to watch it.

What country are you in? What region is your Apple ID mapped to? If not UK for both, you're out of luck unfortunately, cancel.

+1, thank you, I stand corrected. If OP isn’t physically in the US with a US Apple ID, it won’t work.

BritBox is for outside of the UK.

BritBox in the UK has been shut down.

BritBox is available in:

• Australia
• Canada
• United States*
• Sweden
• Finland
• Denmark
• Norway

https://help.britbox.com/hc/en-us/articles/360061273014-Where-is-BritBox-available#:~:text=*Subscriptions%20are%20available%20in%20all,BritBox%20in%20any%20EU%20country.

“If you subscribe in the United States or Canada, your subscription can be used in either region; however, show availability may differ. If you subscribe in Denmark, Finland, Norway, or Sweden, you can watch BritBox in any EU country.”

OP doesn’t meet this requirement clearly.