SEP 12.1 RU2 no definition reporting

This is a clean installation of SEPM 12.1 RU2 on Windows 2008 R2 Standard Edition. All 25 test-clients including local SEP 12.1 RU2 installation fail to report to SEPM about their definition-status. There is no problem when I look on the SEP client itself, the definitions update through SEPM when in-house and through LiveUpdate when out-of-office. The SEP clients also fail to report last-scan status. All other reporting and communication seems to be ok though...

I have tried re-installing some clients and used sylink-drop on a few but neither helped.

Please help!