Why does Docker Container exit immediately with exit code 1?

Question

I took over a project and a necessary docker container doesn´t keep running, but instead exits immediately with code 1 after startup. My Dockerfile:

FROM ubuntu:20.04

RUN apt-get update
RUN apt-get install -y mariadb-server

EXPOSE 3306

LABEL version="1.0"
LABEL description="MariaDB Server"

HEALTHCHECK --start-period=5m \
  CMD mariadb -e 'SELECT @@datadir;' || exit 1

CMD ["mysqld"]

Using the command

docker run --name=db -p 3306:3306 -d db

The container starts, and exits after 1-2 seconds. Logs arent that helpful either, they only contain the line

[Note] mysqld (mysqld 10.3.34-MariaDB-0ubuntu0.20.04.1) starting as process 8 ...

I´ve managed to keep it running with an entry point I added, but executing "mysqld" there, doesnt make any difference.

docker run --interactive --tty --entrypoint /bin/sh db

Of course I also reinstalled docker a couple times already. A colleague of mine had no problems at all and it just worked instantly on his machine. Both of us use a Macbook with Intel chip.

Please let me know, if you have any clue to what the problem could be.