Hi @zlamalp,
I have to tell you that my solution is not really working.
Indeed, when I gave you my answer, I've forgotten that I had changed the way I create the /sbin/sogosync file.

In fact, after the creation by running the original script, I modified this file manually in console mode :
sudo mount / -o remount,rw
sudo vi /sbin/sogosync
Then I edited the file in order to fit with the following lines :

export DISPLAY=:0.0 && export DBUS_SESSION_BUS_ADDRESS="$(ps -u phablet e | grep -Eo 'dbus-daemon.*address=unix:abstract=/tmp/dbus-[A-Za-z0-9]{10}' | tail -c35)" && /usr/bin/syncevolution data_base_name

Note : in the above line data_base_name is to be replace by the name of your database.
Then at each execution by cron daemon, the string DBUS_SESSION_BUS_ADDRESS is evaluated.
It would be nice if the original script would be able to put this line in the file itself but I'm not an expert in shell programming so I've no solution to propose.

Hi zlamalp,

I faced the same issue when I wanted to put in place sync script.
I'm using the script given in link on this page :
https://docs.ubports.com/en/latest/userguide/advanceduse/dav.html
The script is on git repository :
https://gist.github.com/boTux/069b53d8e06bdb9b9c97

I don't know if the script you use is the same (line 27 is different).
Nevertheless, when I used this script, the sync doesn't work anymore after reboot of the phone.
It's because the following command :

DBUS_SESSION_BUS_ADDRESS=$(ps -u phablet e | grep -Eo 'dbus-daemon.*address=unix:abstract=/tmp/dbus-[A-Za-z0-9]{10}' | tail -c35)

doesn't return the same value after a reboot.
So you have to evaluate it after each reboot.

To do so, I changed the lines number 96 to 100 (in the script) by these ones :

CRON_FREQUENCY="hourly"

sudo mount / -o remount,rw
COMMAND_LINE="export DISPLAY=:0.0 && export DBUS_SESSION_BUS_ADDRESS=$(ps -u phablet e | grep -Eo 'dbus-daemon.*address=unix:abstract=/tmp/dbus-[A-Za-z0-9]{10}' | tail -c35) && /usr/bin/syncevolution $OC_DATABASE_NAME"
sudo sh -c "echo '$COMMAND_LINE' > /sbin/sogosync"
sudo chmod +x /sbin/sogosync

CRON_LINE="@$CRON_FREQUENCY /sbin/sogosync"
(crontab -u phablet -r;) # only if no other cronjob already exist in the crontab
(crontab -u phablet -l; echo "$CRON_LINE" ) | crontab -u phablet -
sudo mount / -o remount,ro
sudo service cron restart

With these modification, the value is evaluate et each reboot.

Hope it will help you,

Yannick