dockers containers not working after upgrade to omv 4.X

I've just upgraded to omv 4.x. ... omv is working fine. All data is accessible.
In omv 3.0.99 I had 4 docker containers running succesfully

• linuxserver.letsencrypt
• linuxserver.mariadb
• linuxserver.piwigo
• linuxserver.nextcloud

It seems the letsencrypt container is working fine since the certificate is working and the nginx redirect is working.
In the docker-gui plug-in the other containers have status 'running' but I cannot connect.

I am no expert at all and don't have any clue on where to start looking.
Any help would be much appreciated.

Thanks for the hint. It seems my mariadb docker is faulting (due to a corrupt db)