I started my phone in "safe mode" (long press power button until reboot menu appears, long tap "power off" until "reboot to safe mode" menu appears, tap "OK"). After I rebooted back into normal mode all contacts are gone.
What I tried to fix it
I opened Settings > Accounts and reenabled sync for the two EteSync accounts (one for contacts and one for everything else). That did not bring back the contacts.
I opened the EteSync app, tapped on my EteSync account name to open the collections screen, and tapped the two-arrows sync button. EteSync synced all collections, but the contacts where still missing in the contacts app.
Current state
The EteSync app shows my contacts in the journal / "change log".
The contacts app shows EteSync as contact source, it is even the default for creating new contacts.
What I did for the problem to appear
I started my phone in "safe mode" (long press power button until reboot menu appears, long tap "power off" until "reboot to safe mode" menu appears, tap "OK"). After I rebooted back into normal mode all contacts are gone.
What I tried to fix it
I opened Settings > Accounts and reenabled sync for the two EteSync accounts (one for contacts and one for everything else). That did not bring back the contacts.
I opened the EteSync app, tapped on my EteSync account name to open the collections screen, and tapped the two-arrows sync button. EteSync synced all collections, but the contacts where still missing in the contacts app.
Current state
The EteSync app shows my contacts in the journal / "change log". The contacts app shows EteSync as contact source, it is even the default for creating new contacts.
Other info I found online
Device info
Debug Info
Hamburger > Settings > Debug Info