/dev/shm issue

[esannia]

Hi everyone,
I installed the dlandon/zoneminder.machine.learning, created 3 month ago, on Centos 8.
All works fine except for installed monitor in ZM. After a reboot all configured monitor display "Unable to connect to monitor"
Checking into logs I find lines like this "Can't open memory map file /dev/shm/zm.mmap.XX: No such file or directory".
If I recreate a Monitor it works fine until reboot.
I tried giving full permission to www-data user, like suggested in https://forum.proxmox.com/threads/zoneminder-in-a-container-cant-open-memory-map-file-dev-shm-zm-mmap-2.7495/ , but it doesn't work
Any suggestion?