No synchronization of contacts

A couple of days ago I posted about synchronization errors. Now I have narrowed the problem after a few tests:

  1. Adding a new contact in eMClient: the contact will not be in Google Contacts
  2. Adding a new contact in Google Contacts: the contact will not be in eM Client contacts
  3. Changing an existing contact in eMClient contacts: the change does not show in Google contacts. Saving the change in eMClient brings up a common synchronization error message “could not find contact”
  4. Changing an existing contact in Google contacts: the change does not show in eMClient contacts.

So, whatever I want to do (adding new contact, changing an existing contact) I have to do it twice, once in Google contacts and once in eMClient. Each change in eMClient brings up the error message.

Is there a solution for this?

Best,
Danker