I found the problem.
In fact the DigitalOcean droplet use a different keyboard configuration than mine. When I use the character "_ " it puts me in the place "-".
To launch the PostgreSQL container I made this command
docker run -d -e POSTGRES-USER=odoo -e POSTGRES-PASSWORD=*** -e POSTGRES-DB=postgres --name db postgres:10
instead of that there
docker run -d -e POSTGRES_USER=odoo -e POSTGRES_PASSWORD=*** -e POSTGRES_DB=postgres --name db postgres:10
On Windows to overcome this problem I have to use the codes ALT: [ALT + 95] = "_ " and [ALT + 58] = ": "
Thank you for your support.