Forum Discussion

Cynix2000's avatar
New Contributor
4 years ago

On vacation. Use Thunderbird. I can get email but not send it.

Get the following error and response from my ISP

Just from reading the message it appears they (your provider) need to whitelist the IP address possibly. We do not typically troubleshoot issues like this as we do not block and/or filter traffic for your connection.

On Aug 24, 2020 17:10:13, John Johnson wrote:
> I use Thunderbird When trying to send email through my ISP (Cox, Gainesville Fla) I get the following error message. No issues with downloading email
> An error occurred while sending mail: The mail server sent an incorrect greeting: cmsmtp blocked. Refer to Error Codes section at for more information. AUP#CXDNS.
> On their site the info on th error info is as follows.
> CXDNS There was an issue with the connecting IP address Domain Name System (DNS).
> The Reverse DNS (rDNS) lookup for your IP address is failing.The Reverse DNS (rDNS) lookup for your IP address is failing.
> Confirm the IP address that sends your email.
> Check the rDNS of that IP address. If it passes, then wait 24 hours and try resending your email.
> No idea how to do this.
> Cox DNS: Primary DNS: East Coast

3 Replies

  • Bruce's avatar
    Honored Contributor III

    Does "on vacation' mean you're away from home?  If you're away from home, how are you connecting to the Internet?  I'll assume Cox doesn't like to authenticate SMTP with an "outside" IP address.  I could be wrong and you'd only need to change your server settings.

    Why not use Cox webmail?

    • bearone2's avatar
      Contributor III

      let me confirm, after several different hotel stays, trying to use hotel isp smtp settings, doesn't work.

      turns out the hotels had a faster connection in the business center than wifi in the room.

      i use cox webmail when traveling, just don't do any banking.

      i delete clutter, the remainder still on server when i get home.

      • Bruce's avatar
        Honored Contributor III
        hotel isp smtp settings

        Okay...once've piqued my curiosity.  What are hotel ISP SMTP settings?  How would these settings relate to Cox email service?  Do hotel ISP settings involve your Cox username and password?  I will, however, agree it doesn't work...nor should it work.