@lakotaubp Thanks a lot !
it works.
and thanks to @stanwood at the origin of the workaround.

I don't understand why I didn't have difficulties to add my account in July 2018...
why I could see my Google Calendar events on my Ubports Calendar till... few days ... may be till OTA-16 version install !

Is it possible for you ?

Hello.
Since few days I had an Sync error message in Calendar with my Google account.
All new events created in Google Calendar or in Agenda was not synchronized !
I tried to delete my account in System Settings, and to recreate it just after but, ... I can't add my Google account anymore !
Google screen says :
"Impossible de vous connecter.
Ce navigateur ou cette application ne sont peut être pas sécurisés.
Essayez d'utiliser un autre navigateur..."
Is it a regression linked to OTA-16 version ?
Is it only on my device ?
Is it only on Fairphone 2 ?