Lost every events of 2 calendars on 3

[sebschopf]

hi

I use 3 calendars.
The trouble is about the lost of all events of 2 calendars. A couple months ago, I have already lost all events of 1 calendar. I don't understand why it happened.
With an other configuration, I never had issues.

Soft Laptop
LinuxMint 18.2 Sonya
Thunderbird 52.4.0 (64bits)

Soft smartphone
Android 6.0.1 for SM-G900F
Kernel 3.4.0-9493471

App
DAVdroid 1.7.1-ose
aCalendar 1.16.10