Thunderbird will not work with Plus.net

[#1]

Hi,
I am still rebuilding my system afer a nasty Trojan and viral infection and I cannot re-instate Thunderbird which was my default email client.  Basically, I can neither send nor receive and I get an error message: Server does not support RFC 5746.  How do I get round that one, please.
Alex

[#2]

Probably security related - have a look here http://www.plus.net/support/email/setup/tbird3_setup.shtml section 8

[#3]

Thunderbird will work with Plusnet as long as you're not trying to use TLS (which I think you are).