[Evolution] Not able to delete an appointment in Evolution 3.28.5-0ubuntu0.18.04.1

[m v linschoten gmail com]

I am not able to delete an appointment in my gmailcalendarin evolution,
There's a message that says: Object not found.
I did manage to delete it in my gmail calendar on my phone. But
thesynchronisation seems not to be working.
Greetings,

Mirjam