I can't access "learning content mapped to UK curriculum"

Hello,

I can't access the content linked in this page:

Minecraft Learning for England | Minecraft Education

When trying to login with my @learntomine.onmicrosoft.com account, I get the following error message:

Selected user account does not exist in tenant 'Microsoft' and cannot access the application '00000003-0000-0ff1-ce00-000000000000' in that tenant. The account needs to be added as an external user in the tenant first. Please use a different account.

What am I doing wrong?

Thanks,

Davide