Invisible stmp and URL



The problem is on an iMac 500 indigo running OSX 10.2.8 with all security updates. Recently the DSL modem was replaced and then:

First Mail wouldn't connect to the POP server. Connection error messages is all it displays, although POP, SMTP, accounts and passwords are correctly entered on Mail's settings.

At the same time the website of that very same E-mail Provider became unreacheable....but any other URL is opened flawlessly in Safari or Explorer,
all but the Provider's.

The DSL modem is fine. The connection is OK. An old 5500/250 running 8.6 shares the connection and it is receiving the e-mail content normally on Outlook Express, and also connecting normally to the provider´s main URL.

Can this be fixed?? Is this a Jaguar or a Mail bug?

the invisibles for this iMac:

Thanks In Advance for any ideas.