Unblocking User Emails from OneTrust's Default SMTP

Site admins can unblock valid user email addresses that were initially placed on OneTrust's default SMTP's bounce list due to multiple delivery failures. There are two methods available to remove email addresses from the bounce list and restore email deliverability. This article outlines both methods to help Site admins resolve issues efficiently and ensure users continue receiving email notifications.

Method 1: Email activity tab - Remove from bounce list

Site admins can use the Remove from bounce list self-service option on the Email activity tab of the Email settings screen to remove an email address from the bounce list. This option is available for email activity records that are in Bounced status, allowing Site admins to take direct action without needing to contact support.

Note:

For more information, see Monitoring Email Activity from the OneTrust Platform.

To remove recipients from the bounce list (Email activity tab)

  1. Click the gear icon in the upper right-hand corner to access Global Settings.
  2. On the Global Settings menu, select Email and branding > Email settings. The Email Settings screen appears.

  3. Click the Email activity tab. The list of email activity within the OneTrust Platform appears. Only the past 7 days of email activity is saved.

  4. Click the Context Menu icon corresponding to the bounced email activity record that you want to take action on.


  5. On the Context menu that appears, select Remove from bounce list. The bounce list removal attempt will initiate by sending the user a test email, similar to method 2 below, and will return either a Success or Error message.

Method 2: Users screen - Send test email

Test email notifications can be sent to users within your organization to verify whether their email address is successfully connected to your OneTrust account. When a test email notification is sent to a valid user email address that is currently on the bounce list, this action will automatically remove the email address from the bounce list, allowing the email notification to be successfully delivered to the user's email address. Organizations using a custom SMTP configuration can also send test email notifications to verify email deliverability and further troubleshoot if issues persist.

To remove recipients from the bounce list (Users screen)

If your organization is using the Default Configuration or Send on Behalf of My Domain Configuration for sending email notifications from the OneTrust Platform, then email notifications are being sent using OneTrust's default SMTP (SendGrid). If users in your account are not receiving email notifications as expected, those user email addresses may be on the bounce list. You can use the following procedure to unblock user email addresses from the bounce list to resolve email deliverability issues.

Note:

Organizations using a Custom SMTP configuration can send test emails to users, but any bounce list management will need to be addressed separately with your Custom SMTP provider.

  1. Click the gear icon in the upper right-hand corner to access Global Settings.
  2. On the Global Settings menu, select User management > Users. The Users screen appears.


  3. Click the Context Menu icon corresponding to the user to whom you want to send a test email, and select Send test email. The Test message in progress modal appears. The message on the modal will vary based on whether the user was on the bounce list.
    User Not on Bounce List

    : If the user's email address was not on the bounce list, the user sending the test email will receive the following modal message and email notification indicating that the user was not blocked. No further action is necessary.





    User Removed from Bounce List

    : If the user's email address was on the bounce list, the user who sent the test email will receive the following modal message and an email notification stating the time frame during which emails to the user have been blocked. The user's email address will then be automatically removed from the bounce list.

    Note:

    If the user is still experiencing issues, please reference the FAQ section below.





Default & Send on Behalf of my Domain Configurations FAQ

The following responses are supported solutions to frequently asked questions (FAQ). The OneTrust team continuously monitors these inquiries and will make additional FAQ available as they are identified.

I sent a test email to a user but instead received an email stating that emails sent to the user have been blocked. What can I do to resolve the error?

If you received an email stating that emails sent to the user have been blocked, then the user is on OneTrust's default SMTP's bounce list. Please reference the following list to locate the error you received to identify the cause of the error to resolve.

Mailbox Full

: The following error can be received if the recipient's mailbox has exceeded its storage limit, preventing new emails from arriving.

  • 552 5.2.2 The recipient's inbox is out of storage space and inactive. Please direct the recipient to https://support.google.com/mail/?p=OverQuotaPerm 2adb3069b0e04-549ba84a59asi6177624e87.318 - gsmtp

Account Disabled/Inactive

: The following errors can be received if the recipient’s email account is disabled, suspended, or deleted.

  • 550 5.1.6 User no longer on system:cbraden@email.com

  • 554 30 Sorry, your message to cbraden@email.com cannot be delivered. This mailbox is disabled (554.30).

  • Mailbox unavailable or access denied

  • 550 5.1.1 <cbraden@email.com>: inactive email address

  • The email account that you tried to reach is inactive.

  • 550 5.2.1 The mailbox exists, but is not accepting messages. This may be a permanent error if the mailbox will never be re-enabled or a transient error if the mailbox is only temporarily disabled.

Incorrect Email Address

: The following errors can be received for a typo or an invalid recipient address which results in a non-delivery error.

  • 550 5.1.1 The email account that you tried to reach does not exist. Please try double-checking the recipient's email address for typos or unnecessary spaces. For more information, go to https://support.google.com/mail/?p=NoSuchUser 41be03b00d2f7-af56eab4d92si15378164a12.428 - gsmtp

  • 550 5.4.1 Recipient address rejected: Access denied. [AMS0EPF000001B1.eurprd05.prod.outlook.com 2025-03-18T14:54:58.224Z 08DD65B857980853]

  • 550 5.2.1 <cbraden@email.com>... blank mailhost - invalid address, relay=[167.89.76.99]

  • 550 5.1.6 user no longer on system:cbraden@email.com

  • 550 RCPT TO:<cbraden@email.com> User unknown

  • 550 5.5.0 Requested action not taken: mailbox unavailable (S2017062302). [SJ1PEPF000023D2.namprd02.prod.outlook.com 2025-03-16T17:14:59.303Z 08DD639623DF1113]

  • 550 5.1.1 User Unknown

  • 550 Requested action not taken: mailbox unavailable For explanation visit https://postmaster.gmx.net/en/case?c=r1601&i=ip&v=168.245.100.230&r=1MjQwy-1tVldm1Wwc-00frPm

  • 552 1 Requested mail action aborted, mailbox not found

  • 550 5.1.1 <cbraden@email.com> Recipient not found. <https://www.secureserver.net/help/fix-rejected-email-with-a-bounce-error-40685?pl_id=1592&prog_id=domainspricedright#irbpl_id=1592&prog_id=domainspricedright#irb>

  • 550 5.1.1 <cbraden@email.com>... User unknown

  • 550 permanent failure for one or more recipients (cbraden@email.com:550 5.1.1 <cbraden@email.com>: Email address could not be found, or was misspelled (G8))

  • 5.1.0 - Unknown address error 550-'5.4.1 Recipient address rejected: Access denied. [SJ5PEPF00000205.namprd05.prod.outlook.com 2025-02-19T07:51:31.643Z 08DD500B5710BC1B]' (delivery attempts: 0)

  • 550 5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient cbraden@email.com not found by SMTP address lookup

  • 550 5.2.1 <cbraden@email.com>... Addressee unknown, relay=[168.245.100.230]

  • 550 verify address failed, User not found cbraden@email.com

  • 550 5.1.1 Not our Customer

  • 550 5.1.2 The destination system specified in the address does not exist or is incapable of accepting mail. For Internet mail names, this means the address portion to the right of the "@" is invalid for mail.

  • 550 5.4.4 The mail system was unable to determine the next hop for the message because the necessary routing information was unavailable from the directory server. A DNS lookup returning only an SOA record for a domain name is one example of the unable to route error.

Others

:

  • 550 5.7.193 UnifiedGroupAgent; Delivery failed because the sender isn't a group member or external senders aren't permitted to send to this group.

    • Resolution Guidance: Request your Exchange Administrator to review the group settings and allow the sender to deliver emails to the group. Once unblocked, the emails should be delivered successfully without further issues.

  • 550 5.7.1 The sender is not authorized to send to the destination. This can be the result of per-host or per-recipient filtering.

  • 552 5.2.3 A per-mailbox administrative message length limit has been exceeded.

  • 552 5.3.4 The message is larger than per-message size limit. This limit may either be for physical or administrative reasons.

  • 550 5.7.0 Something related to security caused the message to be returned, and the problem cannot be well expressed with any of the other provided detail codes. This status code may also be used when the condition cannot be further described because of security policies in force.

  • 554 5.7.0 Used when security policy prevents delivery but the specific reason cannot be disclosed.

  • 550 5.4.5 The mail system was unable to deliver the message because the mail system was congested.

The user is still experiencing email deliverability issues. What are some other common issues and causes that I can troubleshoot?

The following are common issues with spam filtering and security settings:

Emails Marked as Spam

: The email client’s spam filters may incorrectly classify an email as spam and move it to the junk/spam folder.

Blocked Sender/Domains

: The recipient may have blocked the sender’s email or domain.

Content-Based Filtering

: Certain keywords or attachments may trigger filtering policies that move or delete the email.

Firewall or Antivirus Blocking

: Security software might block emails due to suspected phishing or malware risks.

The following are common network and connectivity issues:

Client mail server unavailable

: The client device is offline, preventing email retrieval.

VPN or Proxy Interference

: Some VPNs or proxies may disrupt email synchronization.

ISP Blocking Emails

: Some ISPs filter or block emails from specific sources, especially suspected spam.