Yes, sure it is not working. You need to do the update on the command line as shown at the end of the article, for example
For CentOS:
# yum -y update MariaDB-server MariaDB-common MariaDB-shared MariaDB-client MariaDB-compat MariaDB-devel
For Debian:
# apt-get update MariaDB-server MariaDB-common MariaDB-shared MariaDB-client MariaDB-compat MariaDB-devel
This will upgrade to 10.2.29, which should normally solve the issue and enable starting MariaDB again.
Afterwards,
# service mariadb restart