Hello and thanks for you're replay,
I resolved the problem by adding this lines from the official Odoo website (V 16):
map $http_upgrade $connection_upgrade {
default upgrade;
'' close;
}

# Redirect websocket requests to odoo gevent port
location /websocket {
proxy_pass http://odoochat;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Real-IP $remote_addr;
}
And I've add this two lines in my odoo.conf

max_cron_threads = 1
workers = 4

And now It's Working !

I had the same problem and this was the solution.