I already tested this. Passwords are all correct (tested also to connect with other devices - worked), restarted phone, also removed battery. Until now, I did not reset the phone.
What I found on the web is that there are companies offering a "WIFI-Repair for Ativ S", but at prices of 49-69 ?.
All allready done. Tested on 3 routers and networks also different encryptions WEP, WPA, WPA2. also there no connections.
We are using our own Exchangeserver with own certificates, but another Ativ has now problems. Strange.