DAZN sells sport country by country and locks its accounts to the country they were bought in. A German subscriber gets the Bundesliga and Champions League rights DAZN holds in Germany; a Canadian gets the Premier League; a Japanese subscriber gets J.League and baseball; an Italian gets Serie A; a Spaniard gets LaLiga. The same event can be on DAZN in one country and on a rival in the next, and the price differs by country as well.
Where you can watch is decided by the country of your account and by the address you connect from, and DAZN checks both. Within the European Union, the portability rules oblige DAZN to let a subscriber watch their home content while temporarily in another EU country; outside the EU, and for everyone else, a foreign address gets a message that DAZN is not available in your country.
A VPN supplies the home address: connect to the server in the country of your subscription and the service loads. DAZN detects VPN addresses more strictly than most entertainment services because live sport rights are the most expensive it holds, so switching server when one is flagged is routine.
GhostShield has servers in five DAZN markets, Germany, Canada, Japan, Italy and Spain, which covers the subscriptions people ask about most.