[iBook] Can't Post to LEM via G4 iBook

[MacAddictvja]

I've been trying to post messages to three different LEM mailing lists from
my G4 iBook, with no success:

1) CompactMacs
2) Vintage Macs
3) PCI PowerMacs

I am receiving messages daily, but cannot post to any of the above three
lists. I have set Mail on my G4 iBook to Plain Text, but still cannot post
messages. I also tried using Eudora on the iBook, set to Plain Text, but
cannot post from Eudora either. Specs for my G4 iBook: 1Ghz, 768MB RAM, OSX
10.3.9. Mail is working just fine, and so is Eudora. I am subscribed to
dozens of mailing lists, which are all working perfectly, and I am able to
post to ALL of those lists. LEM is the only list that I cannot post to.

What am I doing wrong? I am posting this message from my PowerMac 7300/500.

-- vjamacaddict
PowerMac 7300/500, OS 9.1, 200MB RAM