Before you can Start with KerioConect, you have to install all these Certificates (the whole certificate chain) on your iPhone or iPad or Desktop System

You can get them here:

1. T-Systems Root CA: https://pki.pca.dfn.de/dfn-ca-global-g2/pub/cacert/rootcert.crt

2. DFN PKACA: wget https://pki.pca.dfn.de/dfn-ca-global-g2/pub/cacert/intermediatecacert.crt

3. DFN-CA Global G2-Zertifikat https://pki.pca.dfn.de/dfn-ca-global-g2/pub/cacert/cacert.crt

4. Kernel Server Certificate: https://kernel.rz-berlin.mpg.de/server.cer

Note: On IOS you will find the installed certificate under Profiles

Settings -> General -> Profiles ->

Last Edit: 12.09.2017