You don't say what kind of connection you are making, but I suspect it is to the content server. Have you checked the box "Allow connection using 3G" in CC's settings (Connecting to calibre / Content server connection / IP address & port / Allow connection ...)? This should deal with the first problem and may fix the second as well.
FYI: checking that box tells CC to use any network available, including tethered networks.
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