What does the mailbox unavailable ever mean?
And how do I fix it?
Hi everyone, Leo Notenboom here for askleo.com.
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Well, honestly, I wouldn't be here.
Let's jump right to the question.
"What does SMTP 550 requested action not take at Mailbox Unavailable mean?
I can no longer send emails to my friend at a specific email address at Live Com.
The mail comes back with this message."
Honestly, mailbox unavailable is a frustratingly vague message.
All it really tells you is it didn't work.
That's literally all I can tell you from just that message.
There's a lot of inconsistency as to when that message gets applied and returned.
And unfortunately, there's very little you can assume once you get that message,
all we can do is run down a list of what I'll call the most common reasons
that that message, along with others, might be encountered.
Number one on my list? Bad email address.
Mailbox unavailable usually means
that the email address you're attempting to send to doesn't exist.
Now, that can happen either of two ways.
Either you'll have mistyped email address into the email program you're using,
or the other scenario is if the receiving email address goes away.
Now, that can be when the account is deactivated.
Typically, it's after a while.
In other words, the account gets deactivated,
and some months later, that email address becomes unavailable.
But that's probably the most common cause.
There's some issue with the email address
or the email account that it's being sent to.
Account closed is one of those options.
Account being suspended or hacked is another one.
Some ISPs or some email providers ESPS they will.
Once an account has been hacked, either proactively, close it or suspended.
And when an account is suspended,
they may refuse to accept any further email for that account.
Mailbox unavailable is one of the error messages that can result.
Now, bear with me here.
This one sounds weird, but it actually kind of sort of makes sense.
Your message might look too much like spam.
Now,
it's weird to get a mailbox unavailable message in response to spam,
but one of the reasons that ESPS do this is to basically prevent spammers
from making any assumptions they could if they, like,
start testing their email and if the email providers return
no, this is too much like spam.
This is too much like spam.
Then the spammers could basically learn from that and get better at avoiding spam
filters. By throwing random messages like Mailbox unavailable.
Spammers trying to test the limits of spam filters don't have that feedback to go on.
There could be server limits by that.
I mean, it's possible that what you might
normally see as an over quota error message might instead be responded
to by some email service providers as mailbox unavailable.
When you think about it, it's kind of the same.
You can't deliver email to that account.
The account exists.
The mailbox is just unavailable because it's too full.
Some email providers will in fact return an over quota message.
Others might say mailbox unavailable.
And of course, there could be problems at the server.
Mail servers aren't perfect.
I run a couple of them,
and every once in a while they run into problems, and various errors can result.
So one of the things that can be the cause of a mailbox unavailable scenario is
simply a problem that's out of your control.
It's out of your recipients control.
It's just an issue with their mail server.
The best thing to do to try and make sure
that those kind of problems aren't really what's going on.
Wait a little while and try again later.
If trying again later doesn't work,
which it sounds like you've actually attempted to do,
then the only real recourse is to get in touch with your recipient some other
way and ensure that they're receiving email properly from other recipients or
other senders, or whether or not they've encountered problems of their own.
If nothing else, they can then reach out
to their email provider and ask them what might be going on.
I hope that was helpful.
I hope that helps you understand a little bit more about what mailbox unavailable
might mean for the original article on which this video is based.
For links to related articles,
for comments and updates and more, visit askleo.com/3738.
I'm Leo Notenboom.
This is askleo.com.