Database error while synchronizing data: FOREIGN KEY constraint failed

[Theodore NIKIEMA]

Hello everyone, I would like someone to explain me how to solve this problem:
when I try to send data between controllers and interviewer (by bluetooth) via my menu,
I receive: database error while synchronizing data: FOREIGN KEY constraint failed
i don't understand why and how can i solve this error.

[Boni]

Your Sync.log file please ?