Client sends no internal mail, many mails not shown


we have newly installed Windows 7 PCs with Groupwise Client 2014.2.3.

On these clients are following issues:

- Mails wil not be send

- I see only my mails from the last few days and from before November 2019

If I use the Webaccess everything works fine. I can send Mails to myself and they are shown in my GW-client.

I tried to remove and to reinstall the GW-client, with disabling antivirussoftware too, no effect.

This issue I have on 6 PCs, and it seems, that not all installations with the same client/image will show the same failure.

Any ideas?