A friend , who is on Tiscali, sent me a message about 5 /6 days ago, which never reached me. Today she has received a delivery failure advice entitled as above. What could have caused the failure at the Tiscali or PlusNet part of the chain?

If you view all the headers you should be able to see were its been it could be either of them with a problem but the headers should show it if there is no entery from plus net then they never got it

Thanks, but  can someone give some general reasons for this kind of thing happening? The sort of thing I can tell a basic but curious email user.

If you can't interpret the headers, just post them for someone here to do it.

General reasons are : wrong address, broken server, spam blocker, domain or address suspended, full inbox, black magic, armageddon and smallpox.

  best thought is that she had a box of BM chocs by her side and that corrupted the message, or was it a day when some financial disaster struck (Armageddon)? Inox is that mine? I keep mine as clear as possible.
I presume server down would have to be ISPs?

I like the idea that a box of Black Magic chocs could bounce an email.

Yeah, it could be all manner of different reasons and one I forgot to include was Global Warming. How could I have forgotten to include that catch-all.

Sorry I can't be of more help in pinning it down to specifics but that's what all those characters in the message details are for. Without those it's like clay pigeon shooting from inside a submerged submarine. (I might nominate that one as a demonstration sport for the 2012 olympics.)

I have taken to going through my Spam box on the Webmail. I have found a 'genuine' message there. I just declare it is not Spam, move it to the inbox and then download it. There must be something in the message that identified it as Spam but usually have no idea what it was. The message might be a forward of something, etc. It would be nice, but perhaps impossible, if the offending part of the message that triggered the Spam Checker to say it is Spam to be highlighted in red; you could then advise the sender what it was that got it dumped in your Spam box. I believe, but not exactly sure, that you have to create a Spam box for your Plus Webmail. I also have the feeling that this is off this topic, but I have done it a few times for new people. if you don't have a Spam box then you can't see your Spam; is that right?
PS: My mother liked Black Magic but that was a long time ago - long before DOS and the computer. We had this street party - did not know what it was for at the time but realised much later on it was the end of the war. WW2. Parents never told their children anything. I still don't know very much.