hashem_iMac wrote:
Very helpful answer and it helped me uncover parameters that were unknown to me. However, I am trying to experiment with the Airplane mode. I am connected to a Wi-Fi network and I have the Wi-Fi calling feature turned on. In principle, I should be able to call over the Wi-Fi network but I get the following message "No Network Connection. Connect to a Wi-Fi network or disable airplane mode to place a call." So it seems there is another factor that I am not considering
I just did some troubleshooting. I have 2 home Wi-Fi networks; it works with one, not with the other. And I have used Wi-Fi calling when traveling internationally using hotel networks, so it is either wideband network dependent (i.e., your ISP is blocking Wi-Fi calling), or there is a router setting that is blocking Wi-Fi calling. Specifically, Wi-Fi Calling uses ports 500 and 4500, so these must be open on your router.