Authentication is the entry ticket, not the whole game. Here is the setup to hand your IT team, plus the list hygiene and reputation work that decides whether you reach the inbox or the promotions tab.
Flow is now the automation engine under Marketing Cloud Next, which means marketing operations people need a working mental model of it. Not to build everything — to know what to ask for, and what to refuse.
A sync queue that never empties is not a mystery. It is almost always one of three causes, and each has a specific fix. A diagnostic walkthrough plus the monitoring that keeps the queue at zero.
Marketing Cloud Next gives you several flow trigger types instead of one journey entry source. Picking the wrong one is the most common early mistake — and the most expensive to unpick six months later.