I've come across wifi zones which allow normal web browsing, WhatsApp messaging (including pictures), but not WhatsApp calls. I saw it first in Hollyhead Port w

I've come across wifi zones which allow normal web browsing, WhatsApp messaging (including pictures), but not WhatsApp calls. I saw it first in Hollyhead Port while waiting for a ferry. WhatsApp threw up an error message saying that calls were disallowed by the wifi network.