How to Fix Dynamics 365 Email Not Sending Problem
                     How to Fix Dynamics 365 Email Not Sending Problem
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What is Dynamics 365 
Microsoft Dynamics 365 is a suite of intelligent, cloud-
based business applications that combine Customer 
Relationship Management (CRM) and Enterprise 
Resource Planning (ERP) functionalities, offering AI-
powered tools for managing sales, service, finance, 
operations, and supply chains, seamlessly integrating 
with other Microsoft products like Microsoft 365 for a 
unified view of business processes and data. 
Techniques To Fix Dynamics 365 Email Not Sending Problem
1) Immediate Troubleshooting Checklist
● Test & Enable Mailbox: Navigate to Settings > Email Configuration > Mailboxes, select the user, and click Test & Enable 
Mailbox.
● Approve Email: Ensure the email address is approved by a global/exchange administrator.
● Check Alerts: Review the alerts section in the mailbox record for specific error codes.
● Verify Credentials: Re-enter the mailbox password in the email server profile. 
1) Detailed Fixes
1. Server-Side Synchronization Configuration:
1. Ensure the Email Server Profile is active and configured for the correct outgoing port (typically 587 for SMTP or 995 for 
POP).
2. Verify that Server-Side Synchronization is selected for outgoing email.
2. Security Roles & Permissions:
1. Confirm the user has the required privileges to send emails (e.g., prv Write Email, prv AppendTo Activity).
2. If sending on behalf of another user, verify the "Send Email as Another User" privilege is assigned.
3. Exchange/Office 365 Settings:
1. Verify that Authenticated SMTP is enabled on the Microsoft 365 user profile.
2. Check that the mailbox is not full.
4. Network/Firewall Issues:
1. If using on-premises Exchange, ensure firewalls allow communication from Dynamics 365 Online IP ranges. 
Causes & Troubleshooting steps
● Mailbox Unapproved or Inactive: Navigate to Settings > Email Configuration > Mailboxes. Change the 
view to "Active Mailboxes," select the mailbox, and click Approve Email. Then, click Test & Enable Mailbox.
● Incorrect Configuration: Verify the Server Profile, username, and password are correct. Ensure the 
outgoing server settings are accurate.
● Missing Security Permissions: Ensure the user has the "Send Email as Another User" privilege, 
especially if using workflows.
● Mailbox Disabled: If a user's license is removed or they are deactivated, their mailbox automatically 
becomes inactive in Dynamics 365.
● Server-Side Sync Errors: Check the Alerts section within the mailbox record to identify specific error 
codes related to authentication or SMTP.
● Exchange/SMTP Issues: If using Exchange Online, ensure authenticated SMTP is enabled for the user 
profile.
● Workflow/Automation Issues: If an email is sent via workflow, verify that the owner of the workflow has 
the correct permissions and that their mailbox is enabled. 
How to fix Microsoft not sending emails?
● Clear the Outbox.
● Disable Outlook Add-ins.
● Check for Server Issues.
● Review Antivirus and Firewall Settings.
● Verify Email Account Settings (SMTP)
● Update Outlook.
● Repair Outlook Profile.
● Recreate Your Email Account.
Conclusion
In conclusion, Microsoft Dynamics 365 
email sending problems are rarely due to a 
single, permanent bug, but rather stem from 
misconfigurations in Server-Side 
Synchronization, mailbox approval statuses, 
security roles, or service limits (such as 
daily exchange limits).