Agoraphobia is a fear of being outside in a public place.
If you do not suffer from agoraphobia in waking life, but suddenly experience an attack of agoraphobia in a dream, it can be a sign that something is making you feel vulnerable.
You could be afraid of how others will react to a decision that you have made.
The location where you suffer your attack of agoraphobia in your dreams can have relevance.
If you dream that you suffer a panic attack in a crowded market, for example, you may feel that you are unable to make a difficult choice.
If you have an attack of agoraphobia while at the beach, you could be afraid that you have been relaxing too much when you have important responsibilities.
If you dream that someone else suffers from agoraphobia, you could be worried that they have been placed in a vulnerable position.