Problem Sending emails from Outlook

Sometimes I live in the UK and sometimes in France. When working in the UK, using a landline wireless network Outlook works fine.

When in France, I use a shared wi-fi service because I have no landline. I can receive mail via Outlook, but I cannot send. When testing, I have received several different error message, including one suggesting that I was sending spam, but the most common tells me that "none of the authentification methods supported by this client are supported by your server."

I have tried several of the solutions suggested by members but, sadly, to no avail. Previously, I have turned to a different email agent to solve the problem, which eventually led to all sorts of collation and filing problems. I have decided that, from now on, I don't want to change to a different email agent, so any further inspiration would be gratefully received.