Forum Discussion

LPCaillouet's avatar
LPCaillouet
New Contributor
2 years ago

Cox SMTP Access Blocked for Vacation Home IP Address

Cox is the ISP at home in Louisiana.  On Cox WiFi there, I am successful in using either Microsoft Outlook on my Windows 10 laptop or Mail on my iOS 15.7 iPhone (with cellular data either on or off) ...
blacklist
IP blocked
SMTP access
TiffanyR's avatar
TiffanyR
Former Moderator
Hello LPCaillouet,

I am sorry you are having trouble sending emails with SMTP. If you have not already, I would recommend following the instructions under Contacting Cox for Assistance at www.cox.com/.../email-error-codes.html to see if we can offer any additional insight into getting the IP unblocked to allow sending emails. Please let us know how it goes.

Tiffany R.
Cox Support Forum Moderator
LPCaillouet's avatar
LPCaillouet
New Contributor
2 years ago

The code I get is CXDNS, as reported in my original post.  That code suggests ..

“There was an issue with the connecting IP address Domain Name System (DNS).  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.”

This has been going on for several months now, so I needn't "wait 24 hours and try resending".

Any advice about next steps?

  • Darkatt's avatar
    Darkatt
    Honored Contributor
    2 years ago

    The cxdns indicates a problem with the IP address, and it's DNS related. Wish I could be more help, but at this point the ONLY way this get's fixed is to contact your ISP and have them ensure they have their DNS for the IP address setup correctly, and THEY will need to contact Cox to get this squared away. 

    • LPCaillouet's avatar
      LPCaillouet
      New Contributor
      2 years ago

      Thanks very much for your insights!