The Apple Watch issue should be independent of the iCam Pro-to-iCamSource Pro connectivity, but if you do not have a strong 3G/4G connection, the watch alert may not be shown if it cannot be downloaded quick enough before you raise you arm to view it.
Also, the watch connects to your phone via Bluetooth when not on WiFi, so if you are using any other Bluetooth connectivity (streaming audio, etc.) it can make it more challenging for the watch alert download to complete in time.
How many "dots" of 3G/4G signal do you have when you are having these problems?
Additionally, when using both the Public and Private Proxies, the Public ones will be tried first before falling back to your Private data, but they are not as performant as our Private server.