Sending email blocked by hotspot IP provider

Often when travelling and connecting to hotspots, I find that I cannot send email from my outlook client. My home provider requires that the outgoing maile be authenticated. Apparently many hotspots do not support this (or block it out).

In order to send email from a client, one needs to open the account settings in outlook, open outgoing server tab, and uncheck the "Requires authentification on outgoing mail" box. So far it works for all the hotspots.