Hi Vlk - thanks for your quick reply. I think I did something like this when setting up the post part:

There was a sequence of windows, one of which saying that I should change SMTP/POP3/MAP4 server address to 127.0.0.1. Two windows ahead, the addresses turned up and I put the number in… wrong?

One more thing: In FAQs there is a question about dial-up connections - that they could or should put a setting into one of the files. Is this a recommendation for all dial-up customers?