In this tutorial:

Our Systems Team has begun implementing the requirement of SMTP authentication on our servers that may affect customers using an email client such as Thunderbird, Outlook or Mac Mail. If you are receiving "550 Access denied - Invalid HELO name" (or a similar error message) in your email client, please check your settings as follows:

Microsoft Outlook

  1. From the Menu Bar, Click Tools then Click E-mail Accounts
  2. Select View or change existing e-mail accounts then Click Next
  3. Select your Email account then Click Change
  4. Click More settings
  5. Select Outgoing Server tab
  6. Select the box beside My outgoing server (SMTP) requires authentication
  7. Select Use same settings as my incoming email server
  8. Click Ok
  9. Click Next
  10. Click Finish


  1. From the Menu Bar, Click Tools, then Account Settings
  2. This will bring up the Account Settings window where you can click on Outgoing Server (SMTP) at the bottom of the list in on the left side of the window. Back in the middle of the window, select the appropriate outgoing server and click the Edit button.
  3. Make sure Authentication method is set to Normal password
  4. Click OK to close the SMTP edit window and again on the Account Settings window.

Mac Mail

  1. From within Mac Mail Click Mail, Preferences, then Accounts
  2. Near the bottom of the window, look for Outgoing Mail Server (SMTP), click the drop down arrow and select Edit SMTP Server List...
  3. Click the Advanced button in the middle of the window and make sure Authentication is set to Password.
  4. Click OK to close the edit window
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n/a Points
2014-03-31 1:17 am

What is the settings for SEAMONKEY?  I'm able to send normally on all my accounts except for one. Keep getting the 550 spam error when I try to send.

16,266 Points
2014-03-31 4:48 am
Hello Joyce,

Thank you for your question. You can certainly set SMTP authentication with SeaMonkey. The instructions should be the same as the ones for ThunderBird.
If these instructions are a bit unclear, you can also view Mozilla's own set of instructions here.

Kindest Regards,
Scott M
n/a Points
2015-09-09 9:31 pm

Im using squirrel mail- what do i do? and when i tried to reposnd to the technicians email who gave me this link it wont send "Message not sent.

Requested action not taken: mailbox unavailableServer replied: 550 This message was classified as SPAM and may not be delivered. For moreinformation, please see"

17,314 Points
2015-09-09 10:47 pm
Hello Heather,

Sorry for the problems with the email. I would need to see the contents of the email that you replied with. Did you include a copy of the email you tried to previously send? It's possible that the email security is tagging your email content as spam. If this is not the case then you will need to submit a support request directly to have it reviewed. You can do this in AMP without having the email bounced.

I hope that helps to answer your question! If you require further assistance, please let us know!

Arnel C.
n/a Points
2015-12-29 8:59 am

I connect using Outlook to Exchange and have lots of 550 issues.

As I connect to Exchange over HTTP, there is no option for Outgoing Server tab.

Can you suggest another option?

1,348 Points
2015-12-29 10:04 pm
Hello Stephen,

The article above only applies to using mail with one of our servers. I advise you check a dedicated Exchange forum to find more information about the issues you're having with those services.
n/a Points
2017-08-22 5:02 am

My STMP and other settings in Outlook were already correct, as advised by the above instructions. Still getting 505 error just trying to forward emails to friends. Any other ideas to stop this?

1,348 Points
2017-08-22 4:43 pm
Did you get a 505 error or a 550 error?

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