Messages are delayed and a ‘remote certificate was not validated’ error is reported


Messages sent to Exclaimer Cloud are not being delivered (or delivery is delayed) and the Office 365 message trace shows the following error:

 Reason: [{LED=454 4.7.5 Remote certificate was not validated}


Typically, this scenario occurs if the Mail Routing options in Exclaimer Cloud are configured as Sender Domain. This configuration results in Exclaimer Cloud delivering the message to the server specified on the sending domain name’s MX records.


Configure Mail Routing options in Exclaimer Cloud to deliver the message back to Office 365, instead of the sender domain’s MX records. To do this, follow the steps below:

  1. Log into the Exclaimer portal (
  2. Click the Launch button for your subscription.
  3. Click the Settings button at the top of the page.
  4. Click the Mail Flow
  5. Click the Edit button under the Mail Routing
  6. Choose Static Domain from the drop-down list and then specify the Office 365 domain name (ending

Haven't found a solution to your problem?

Please click the button below, login to the Exclaimer Cloud portal and raise a support ticket. A member of the Exclaimer Support team will then be in touch.

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