"Make sure that the credentials specified in the mailbox are correct and have sufficient permissions" error appears when testing and enabling a mailbox in Dynamics 365

When you attempt to test and enable a mailbox in Microsoft Dynamics 365, you encounter one of the following errors:

• "The email message "Your mailbox is now connected to Dynamics 365" cannot be sent. Make sure that the credentials specified in the mailbox <Mailbox Name> are correct and have sufficient permissions for sending email. Then, enable the mailbox for email processing.

      Email Server Error Code: InvalidOutgoingMailboxCredentials"

• "Email cannot be received for the mailbox <Mailbox Name>. Make sure that the credentials specified in the mailbox are correct and have sufficient permissions for receiving email. Then, enable the mailbox for email processing.

      Email Server Error Code: InvalidIncomingMailboxCredentials"

This error can occur if credentials are not provided in the mailbox record or if the credentials are not sufficient to access the corresponding mailbox.

1. Navigate to Settings, Email Configuration, and then click Mailboxes.

2. Change the view to Active Mailboxes.

3. Select the mailbox encountering this error and then click Edit.

4. Within the Credentials section, verify the Allow to Use Credentials for Email Processing is set to Yes and the correct User Name and Password to access the corresponding mailbox are provided.

5. Click Save and then click Test & Enable Mailbox.

6. After the tests complete, view the Alerts section if the results do not appear as Success.