what does this error message mean?

  palinka 10:27 25 Oct 2008
Locked

A friend sent me an email which bounced back to her with this message: Undeliverable.......5.1.0 - Unknown address error 550-'(result of an earlier callout reused).'
The address she'd sent it to was correct.
What does "result of an earlier callout reused" mean?
She's a newbie and we're exchanging emails just so that she gets daily practice; if she's doing something odd I'd like to sort it out sooner rather than later.
She's with Talktalk.

  birdface 10:37 25 Oct 2008

Probably your e-mail is treating it as spam and sending it back.So probably a problem at your end.

  birdface 10:42 25 Oct 2008

Maybe it has been put into your blocked senders by mistake.

  birdface 10:45 25 Oct 2008

Googled.click here= it will give you something to look at until someone can give you the advice that you need.

  Kalb 10:47 25 Oct 2008

Most probably SMTP Authentication is not activated or switched on........not sure with Talk Talk but follow this for BTYahoo click here
It explains the reasons why you need it

  palinka 11:34 25 Oct 2008

thanks, everyone; but none of the links - or your suggestions - offers an explanation that fits.
My friend and I have exchanged emails over the last 4 or 5 days without any problems. No, she isn't blacklisted or blocked at my end - I checked that,(in fact she is on my "friends" list). And it surely wasn't the content - we were discussing the weather!

  birdface 12:08 25 Oct 2008

Send her a message and get your friend to click on Reply and see if you receive it that way.

  Kalb 12:22 25 Oct 2008

Have you tried contacting TalkTalk ? It wouldn't be the first time the fault has been at their end !!

  palinka 16:38 25 Oct 2008

thank you both.
I'll try the send message...reply route and see how that goes.
Of course it may just be a one-off event.

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