Mac/Lycos Mail/ntlworld.com issue?

[National Nick]

Using Lycos Mail [the 'basic' or 'free' service], with a Mac G4 running OS X 10.4.8 and Firefox 1.5.0.7, emails to users at ntlworld.com are consistently undelivered while emails to other addresses get through normally. It appears that emails get to Lycos which then denies that the receiver at ntlworld.com exists. Emails to ntlworld.com via Lycos appear to get through normally when using a PC [at a public library so don't have the exact details but it's liable to be pretty basic]. I could download Firefox 2 but otherwise I'm stumped. I used to use Safari but that wouldn't include the original mesage in my reply despite the Preferences in Lycos being set correctly.
I would be very grateful for any suggested solutions.
TIA
National Nick

[Jazz]

I would personally contact Lycos - Open New Support Ticket.

Although you can email NTLWorld accounts from the library computers, I remember Hotmail having issues with NTLWord due to the fact that they performed a software upgrade, which included 'aggressive junk mail filtering'. However, this was later resolved.

However, saying that, you may have more luck if you were to post at a specialized Mac/OS X 10.4.8 forum, IMO.

Just a suggestion.