All of my mailadresses are lost

All of a sudden all of my mailaddresses are gone HOWEVER if I compose a mail, the mailsystem does find the address. But when i try to see all of my mail addresses on the screen, none pops up.
It seems that this has a link with the following message:

“”[Google Contacts]Het uploaden van item(s) naar map ‘coordinator.pga@gmail.com/Contacts’ is mislukt met de volgende foutmelding: Can not remove all contact group memberships. Contact must always be in at least one contact group"".

Pls your advise how to solve this problem. On request I can inclose the logging file

Thanks a lot in advance!

The simplest solution is to remove the Gmail account from eM Client, then add it back again.

Before removing an account, make a backup using Menu > Backup, just to be safe.