Collector for Arcgis: The Server you are trying to connect cannot be verified

[Electricity_Company_of_Ghana_L]

I have setup an on-premise Arcgis server 10.4.1  which has been used for field data collection. Surprisingly over the last week, I did a minimum update on the server and I persistently get a dialog stating "The Server you are trying to connect to cannot be verified". The service has been restarted multiple times but get same error. Features cannot be accessed on the collector application anymore. An urgent help is really needed.

[RayGreen]

Were you ever able to resolve this issue?  I know it is a while back, but we are still having this problem on android systems.

[SiCasley]

The issue for us was that our CA certificate (.pfx file) didn't contain the complete certificate chain. Once we had created a new .pfx that included the root and intermediate certificates and installed that on AGS (along with installing the root and intermediate separately in AGS as well) we didn't have any more problems.

[RayGreen]

Simon thank you!  We had installed our certificate on AGS, we had installed the certificates on the units, and had just about given up getting this to work until your reply mentioned the intermediate certificates.  I had gone through plenty of threads and none ever really had an answer until yours.