Error 554 5.2.2 permanent exception with message recipient is not resolved

Question

Getting this error mostly when using outlook desktop app to send mail to shared mailbox. But I use outlook on the web, it will deliver successfully. I have tried some tips gotten online like toggling on/off focus group, but the error still the same. The error message is given below:

STOREDRV.Submission.Exception; failed to process message due to a permanent exception with message recipient 'recipientName' is not resolved. All recipients must be resolved before message can be submitted. InvalidRecipients Exception: Recipient 'recipientName' is not resolved. All recipient must be resolved before a message can be submitted.
[Hostname=AM0PR10MB3251.EURPRD10.PRODUCT.OUTLOOK.COM

Answer 1

Hi @lanre mufu ,
Can other user mailboxes send emails to this shared mailbox through the Outlook client?
Is it normal for you to send emails to other users' mailboxes or shared mailbox through the Outlook client?
According to the information you provided, the error may be related to the Outlook client, please try the following steps:

1. Please try to remove the auto-completed address and manually type the shared mailbox address, then send the test email to shared mailbox again.
   
2. Please try to create a new outlook profile, then hold the “Windows” button and “R”, type the “outlook /safe” in the “Run” to start the outlook as safe mode. Send email to shared mailbox again.
3. In addition, if possible, you could also try to upgrade your Outlook to the latest version.

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