Systemd enabled services not starting at boot anymore

I made some custom systemd services long time ago, all have the same configuration (except for the ExecStart of course)

This configuration worked for years, I have ubuntu up and running since version 18.04 LTS, but now looks like some of these systemd services aren't starting at boot at all, the configuration is as follow (myapp.service):

[Unit]Description="myapp"After=syslog.target network-online.targetWants=network-online.target[Service]Restart=alwaysRestartSec=10User=rootGroup=rootWorkingDirectory=/opt/myappExecStart=/usr/local/bin/myappKillMode=control-group[Install]WantedBy=multi-user.target

The service is enabled:

$ sudo systemctl enable myappCreated symlink /etc/systemd/system/multi-user.target.wants/myapp.service → /lib/systemd/system/myapp.service.

If i do "systemctl status myapp" after a reboot:

● myapp.service - "myapp"   Loaded: loaded (/lib/systemd/system/myapp.service; enabled; vendor preset: enabled)   Active: inactive (dead)

If i do "journalctl -u myapp -f" after a reboot:

Jan 13 12:10:06 myhost systemd[1]: Started myapp.Jan 17 07:15:03 myhost systemd[1]: Stopping myapp...Jan 17 07:15:09 myhost systemd[1]: Stopped myapp.

What's wrong with my configuration?

If I manually start /usr/local/bin/myapp there are no errors on the script and I've also tried running it with tmux, now it's 3 days running in bg and no errors. But systemd just won't start it after a reboot.

Today, i've also tried to install a new service that require a systemd config, the package is zram-config and by default it is enabled at boot.But after a: apt install zram-config && sudo reboot:

$ sudo systemctl status zram-config● zram-config.service - Initializes zram swaping   Loaded: loaded (/lib/systemd/system/zram-config.service; enabled; vendor preset: enabled)   Active: inactive (dead)

but if now i do:

$ sudo systemctl start zram-config$ sudo systemctl status zram-config● zram-config.service - Initializes zram swaping   Loaded: loaded (/lib/systemd/system/zram-config.service; enabled; vendor preset: enabled)   Active: active (exited) since Mon 2020-01-27 12:25:55 CET; 1s ago  Process: 5541 ExecStart=/usr/bin/init-zram-swapping (code=exited, status=0/SUCCESS) Main PID: 5541 (code=exited, status=0/SUCCESS)Jan 27 12:25:55 myhost systemd[1]: Starting Initializes zram swaping...Jan 27 12:25:55 myhost init-zram-swapping[5541]: Setting up swapspace version 1, size = 985,7 MiB (1033568256 bytes)Jan 27 12:25:55 myhost init-zram-swapping[5541]: nessuna etichetta, UUID=4ac5c2cd-0c68-4f6d-a5c0-d8f91a509c71Jan 27 12:25:55 myhost init-zram-swapping[5541]: Setting up swapspace version 1, size = 985,7 MiB (1033568256 bytes)Jan 27 12:25:55 myhost init-zram-swapping[5541]: nessuna etichetta, UUID=83a4f201-d591-4222-89a6-5bc5aebedef4Jan 27 12:25:55 myhost init-zram-swapping[5541]: Setting up swapspace version 1, size = 985,7 MiB (1033568256 bytes)Jan 27 12:25:55 myhost init-zram-swapping[5541]: nessuna etichetta, UUID=1f6f742e-6fb8-4332-b226-bf6918f7ee28Jan 27 12:25:55 myhost init-zram-swapping[5541]: Setting up swapspace version 1, size = 985,7 MiB (1033568256 bytes)Jan 27 12:25:55 myhost init-zram-swapping[5541]: nessuna etichetta, UUID=a5509c55-46f5-4112-8fe1-68171f31409eJan 27 12:25:55 myhost systemd[1]: Started Initializes zram swaping.

I really don't understand what's wrong with systemd on my Ubuntu install, is it better I do a fresh reinstall of whole OS?

Thanks