Sudden Xibo SQL Error

This error started suddenly. The application was working fine for almost 2 years.

please see the docker ps output below

CONTAINER ID        IMAGE                                COMMAND                  CREATED             STATUS              PORTS                               NAMES
559d4c54be0b        xibosignage/xibo-cms:release_1.8.2   "/entrypoint.sh"         8 days ago          Up 9 minutes        0.0.0.0:80->80/tcp                  xibo_cms-web_1
ba3977b8b3db        xibosignage/xibo-xmr:release_1.8.2   "/entrypoint.sh"         8 days ago          Up 9 minutes        0.0.0.0:9505->9505/tcp, 50001/tcp   xibo_cms-xmr_1
e94e6379c85a        mysql:5.6                            "docker-entrypoint..."   8 days ago          Up 9 minutes        3306/tcp                            xibo_cms-db_1

You’re running a MySQL server in the containers. This thread relates to running with an external MySQL server.

Fatal Error - sorry this shouldn’t happen. SQLSTATE[HY000] [1130] Host ‘localhost’ is not allowed to connect to this MariaDB server, this happened when I try to open it! how could i resolve this!