Helping people with computers... one answer at a time.
Hitting Reply sends a message back to the person who sent the original, right? Not always. I'll look at how and why a Reply might actually bounce.
I have received emails from several people but when I try to respond, the message gets kicked back as 'Permanent fatal errors' and 'Reason 550: user unknown' as an incorrect email address. I am using the email address that the message was sent with, so how can it be incorrect? Is there anything that I can do?
You get an email.
You reply to it.
You get a message back that your reply bounces ... how's that possible if you never even typed in an email address? You never had the opportunity to get it wrong - you just replied to the address it was sent from, right?
There are two common scenarios that can cause this. But first, we need to talk about that "From:" address.
When you receive an email, it typically has headers that look much like:
Now, looking at that, you would assume that the message came from the person who's email address is "firstname.lastname@example.org".
It may not have.
The big secret is this: the "From:" line on an email is simply set by convention - it is not required to be the email address that the message came from, and it's not enforced to be that by any email software along the way.
Now, 99.99% of the time, it is in fact the email address of the sender because the sender wants you to be able to reply, and most email programs default to setting it that way.
But it's not a requirement.
As I said, there are two common cases where it's not the sender at all.
You probably saw this one coming.
It's easy to set the "From:" address to whatever a spammer wants to set it to. In order to make it that much more difficult to track down spammers, they often set the "From:" address to be something completely unrelated to the email that's being sent, and most certainly not the email address of the actual sender.
Frequently, spammers will set the "From:" address to another address on their list of addresses to spam. Reply to that spam and the person who gets that email might have no idea what you're talking about because they didn't send it.
Or spammers might just make it all up - the From: address might not be valid at all.
Reply to it and your message might bounce.
Let's go back to the day that you configured your email account in your email program. Somewhere along the line, you were asked to enter your email address:
Here's another deep dark secret; two of them in fact. For many, many email programs:
This entry is only used as what will be placed in the "From:" line for emails you send.
It may not have to be right.
That last one surprises people, but in fact, it's often useful to be able to send email from a different email address as the one on which you receive email. (It's usually the account user ID and password specified elsewhere that actually gains this person access to their account. While the user ID might indeed be the email address for many email services, it is not for many others, and thus, it is a completely separate setting.)
Here's the human error part: you'd be shocked at how often people mistype their own email address. I see it all the time in questions submitted to Ask Leo!. I'll reply with an answer and ... bounce.
What that means is that all that had to happen was for the person who sent you that email to have mistyped their own email address when they configured their email client. The "From:" address would be invalid, and neither you, nor anyone else who received email from them, would be able to simply hit Reply and have it work.
If you reply, it might bounce.
The only thing that you can do is check the email that appears when you hit Reply and make sure that it's their correct email address, assuming that you know it. If you do, and note a difference, then type in their correct email address into the To: line instead. Of course, you may want to let them know that there may be a problem in their configuration.
This is much more unlikely in day-to-day use, but I'll mention it for completeness as it could suffer from the same problem.
There is an additional, optional, and often hidden email header called "Reply-To:"
This header is a specific override for the reply function. It indicates that when the recipient replies to this message, the reply is to be sent to this different email address.
Naturally, it can be forged by spammers and mistakes can be made by those using it for legitimate email.
In either case, the discussion is as above: reply and your message might bounce if the Reply-To header has an incorrect email address.
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