Accounting firm

ACO, a company resident in country A, carries on a video streaming
business. In return for monthly subscription fees, customers are able to watch
videos online, and are able to download copies of videos on to their mobile
devices in order to watch the videos offline (for a limited period).
ACO is the owner or licensee of the copyright in its library of videos. ACO has
many individual customers in country B. These individual customers enter into
subscription contracts with ACO on ACO’s website. Monthly subscription
payments are made to ACO by the charging of customers’ credit cards
(evidenced by invoices which ACO sends to customers’ email addresses).
ACO has no physical presence in country B. However, ACO is registered for
goods and services tax (known as VAT) in country B, and has appointed an
unrelated accounting firm (BCO) in country B to act as its VAT agent.
In accordance with country B law, ACO charges VAT on its invoices to
country B customers. Country A and Country B have concluded a double tax
treaty in identical terms to the 2017 OECD Model Tax Convention (MTC).
Discuss whether country B is allowed to tax the income received
by ACO from its customers in country B under the A/B treaty?