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Thread: 550-Mailbox not available

  1. #1
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    Default 550-Mailbox not available

    Hi all,

    W had a third party server which was relaying messages to external domains.Now since the subscription has ended i was trying to relay mails through may mail server.Few domains are not accepting my mails and bouncing

    550:mailbox not available

    Initially i thought issue was with reverse PTR entry and fixed it with help of ISP.Still lot of domains are not accepting my mails when relayed through my mail server.

    Can someone help me in fixing this issue? I'm ready to provide the logs if required.

  2. #2
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    Default

    Hi mrdoubt,
    Check this steps one by one, and tell us if works:
    Zimbra: Best practices, enviando a Gmail, Hotmail, etc » Blog de Jorge de la Cruz

    I can provide to you also, a free 15 days service of Relay SMTP, since you fix the problem.

    Kind regards

  3. #3
    Join Date
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    Default

    Hi,

    Check your domain status with "mxtoolbox.com" just to make sure that you are not in any blacklist and that your basic SMTP configuration is ok.

    Most of the major e-mail providers will block any mail (or at least mark it as spam) that comes from a brand new IP address (microsoft is the most strict in this sense, while yahoo and gmail will only put your mails into spam folders).

    Make sure you are doing what you can in order to "get the lower spam rating possible". Things like having the SPF record in place, properly announcing your reverse IP in your SMTP banner, etc.

    My recommendation would be to use a proper service like the one jorgedelacruz.es is telling you about (BTW, very cool that he offers this for free at least for 15 days! )

    Regards and good luck with this!
    Sebas

  4. #4
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    Hi pub_seba
    Thank you for your words

    mrdoubt, test your IP in SenderBase too, it's the first list in the world, and many providers check inside it.

    Also Senderbase, or announcing your reverse IP inthe SMTP banner, SPF, DKIM, etc, are propertly explained in the post (spanish I'm sorry) that I gave to you.

    Kind regards

  5. #5
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    Default

    I have checked everything,PTR,senderbase,SPF ,DNS everything seems fine.I'm still receiving the error with few domains

    550 Requested action not taken: mailbox unavailable (in reply to RCPT
    TO command)

    I'm confused why i'm not able to relay through my own mail server but can send messages to those domains through a third party server.

    I feel that there are few more issues with respect to my dns records.

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