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Only on Outbound emails I get the following error.  Just started yesterday.  I've checked all the settings, etc. and everything is right.  Can't figure it out.  Can anybody help?

An error occurred while sending mail. The mail server responded:  5.2.0 3Ton1x0010PnBoL01TonSu internal error. Please check the message and try again.


  • Hi, please review this link: to see if that corrects your issue.  If it doesn't, send us a message on Facebook, Twitter or email us at for additional assistance.  We're here to help!  Thanks, 

  • CarolLM - I did that already.  I read and did everything I can think of.  My settings are okay and I can send thru gmail.  But if I try to send to a large number of people using my Cox email it won't send and I get that server error message each time.  I used to be able to do this and now can't.  It's not my email client if I can send thru gmail.  It's a problem with Cox.

    Any other suggestions?

  • I have the same problem. "Brian from Cox" had a post on this and I did everything the post stated - on Changing your e-mail server settings for Microsoft Outlook 2007-2016 (I have 2007) and it worked one time. After that it started giving me an error message that "Relaying not allowed" to any recipient.  After several more tries it gives me an error message of "too many bad command" - it also gave me message one other time to the effect that the sever does not accept encrypted messages. This all started when cox made a change to the encryption settings. Is there any plan to fix this? 

  • I have the same problem.  I called Cox support today and after searching for awhile, the technician confirmed internal documentation that Cox now has a email sending limit of LESS THAN 10 email recipients.  Otherwise you get that error message.  This is all new within the last week.

    Cox, how about changing that error message to something informative such as "Error.  maximum of 9 email recipients allowed."

    Of course this is ridiculous.  Users can't send out emails to nearby neighbors, boy scout members, church choir members, etc.  How would Cox even send emails to their own tech support department employees?  I'm sure there are more than 9!

  • Cox has sending limits in place for outbound email. These limits are intended to reduce the amount of unwanted spam on the Internet by identifying and containing “spam bot” attacks generated from Cox customers’ PCs. These limits are set very high, and it is unlikely that normal residential mailings will surpass the limits. Cox has chosen sending limits based on other ISP’s best practices and analysis of existing email traffic to insure even large legitimate residential mailings complete with no errors.

    Please resend your message using Cox Webmail instead of your current email utility ( I successfully sent an email to 10 recipients this morning using my Cox Webmail account.