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MS Outlook for Mac Error Code 17099

Published By Raj
Debasish Pramanik
Approved By Debasish Pramanik
Published On January 15th, 2024
Reading Time 2 Minutes Reading
Category Email Tips

MS Outlook, one of the most widely used email clients, has spread its roots in both Windows and Macintosh operating systems. While there have been several versions of MS Outlook in Windows OS, for Mac operating system only Outlook 2011 and Outlook 2016 are available.

Similar to Outlook for Windows, there are times, when a user encounters errors in Outlook for Mac. One common error that is encountered in Outlook for Mac is Error 17099. The following error message is shown when this error is encountered:

Relaying to prohibited by administrator email could not be sent

Cause of Error 17099

There are mainly two causes associated with the occurrence of this error:

  1. This error mainly occurs when the SMTP server returns a permanent or transient error.
  2. The second scenario when this error occurs is while sending a mail to a large number of users. Since the default limit is 50 users, in case the email is sent to more than 50 users at the same time, this error is encountered.

Workaround to Resolve Error 17099

This error can be resolved with the help of two methods. They are:

  1. If Error is Due to SMTP ServerThis error can be resolved by rebuilding the identity database that can be done with the help of Microsoft Database Utility. For performing this process, follow the below-mentioned steps:
    1. Exit from all the applications that are running.
    2. Open Application folder and browse for MS Office 2011 to search for the Microsoft Database utility and double click on it.
    3. Click on the OLM file that has to be processed in Database Utility Window, and click on Rebuild.
    4. You will see a progress window displaying Rebuilding Main Identity.
    5. Once the process is completed, a message will be displayed “Your database was rebuilt successfully”
    6. Click on Done option.
  2. If The Email Is Sent to Large GroupsIn case an email is sent to large groups in which the number of users is more than 50. For increasing the number of users from 50 recipients, you should contact the mail provider. The mail provider can increase the recipients per message and you can avoid getting these messages.


With the help of above mentioned procedures, we can overcome the occurrence of Outlook for Mac error code 17099.


By Raj

A technical analyst and a writer with innovative ideas when it comes to technology. Provides solutions, tips and tricks to get things done using technology.