Nethvoice PBX in DMZ

Basic system is debian12 and there is timezone ok:

root@pbx:/home/tux# timedatectl
               Local time: Do 2025-02-20 08:49:50 CET
           Universal time: Do 2025-02-20 07:49:50 UTC
                 RTC time: Do 2025-02-20 07:49:50
                Time zone: Europe/Berlin (CET, +0100)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

Where I could control / correct the mariadb timezone ??
mariadb is not active:

root@pbx:/home/tux# runagent -m nethvoice1
runagent: [INFO] starting bash -l
runagent: [INFO] working directory: /home/nethvoice1/.config/state
nethvoice1@pbx:~/.config/state$ timedatectl 
               Local time: Thu 2025-02-20 11:05:52 CET
           Universal time: Thu 2025-02-20 10:05:52 UTC
                 RTC time: Thu 2025-02-20 10:05:53
                Time zone: Europe/Berlin (CET, +0100)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

nethvoice1@pbx:~/.config/state$ mysql --help
Error: no container with name or ID "mariadb" found: no such container
nethvoice1@pbx:~/.config/state$ 

It is a nethvoice-on-debian problem. I found this in forum
NethVoice would not allow me to select or put a timezone
I tried now time zone=MET - hoping this means MiddleEuropeTime
But what means MST ? MiddleEuropeSummertime ?
Have I manually change to summertime ??