Incomplete sync of emails from Gmail since end of January 2019

Since the 30th January 2019 the sync of messages with gmail is incomplete.  (some appaer and some not even after 16 days)

The setup is a IMAP connection / Win 10 PC / last update of eM Client version.
While seeing the e-mail messages in de webbrowser of gmail some of the messages are not downloaded/seen on the eM Client application.
Even a search  in Em Client (maybe it’s somewhere saved in a map I can’t see it) on the missing e-mail message is not showing this message.
The logging is not showing any problem.

Having the gmail connected to the Mail application of Windows all the messages are visible. Instead of reinstalling the gmail account to eM Client, I was wondering what is happening and is there a solution.

Thanks for assistance.