So the MySQL container isn't creating the database and user correctly.
It does so solely on the presence of the
MYSQL_PASSWORD environment variables when the container very first starts up.
One of those is missing, or differs from what's being given to the
web container. As before, you'll need to destroy the container, and remove any locally stored data (
/volume1/xibo-docker/web/cms/datbase if that's still where you have it stored) before you can make another attempt.
Note also you say "still I see", but this is a very different error from the one you showed before
ERROR 1130 (HY000): Host '172.17.0.4' is not allowed to connect to this MySQL server