Seemingly all to do with something called the Lachin corridor.
Nagorno-Karabakh routes reopen in Lachin corridor deal, say Azeri and Armenian sides (The Guardian). Extract:-
Azerbaijan’s government and separatist Armenians in
Nagorno-Karabakhappeared to strike a deal reopening two disputed transport links including a key route known as the Lachin corridor.
The moves – initially reported by Armenia’s Armenpress state news agency and confirmed by
Azerbaijan – appear at least partly to grant the latter’s decades-old demand to restore transport links between Azeri government-held territory and Nagorno-Karabakh, where Armenians seized control in the 1990s.
Karabakh is recognised globally as part of Azerbaijan, but has been controlled by its population of about 120,000 ethnic Armenians since a war that coincided with the breakup of the Soviet Union in the 1980s and 90s.
Azerbaijan recaptured large swathes of Nagorno-Karabakh in a 2020 war, and for the past nine months has exerted pressure by
restricting access to Armenia through the Lachin corridor.