Deno Oak : Can't connect to SSE with Deno Deploy

Hello,
I'm trying to deploy an app who use Server Sent Events. The goal is to keep in memory differents rooms and users when connected.
Actually, i can see rooms being created and users being connected. I store the data of the room in a service but when i try to dispatchMessage on my users to send data, i see in my logs :
user.target.dispatchMessage is not a function

Locally, i don't get this errors. It works perfectly fine.

I add some picture of the code that could help.

Here is the repo :
https://github.com/silvanic/PlanningPoking

Thanks a lot for you help !