Cannot login To BritBox app on Firestick

Hi Amazon I love your Firestick I can access everything very well . The only App that doesn’t t work is the BritBox App. I have a South African based BritBox account but the App keeps saying I am off line and will not allow me to log in. I am definitely online . Other people are also having the same problem with firesticks here in South Africa I have two firesticks and cannot access BritBox on either of them. I do have a BritBox app on my smart tv that I can log into and it works fine. Why can’t I access on the Firestick App??? The Firestick has got a 5star rating from me but the Brit Bix app doesn’t work so gets a 0 from me