An Unknown error has occurred in Outlook – Error Code 17884

Let’s check what causes this Outlook error code 17884 and how can we fix it.

Are you not able to send the email through Microsoft Outlook? If your email is stuck in the Outbox with error code 17884, this post is for you. Outlook is one of the most prevalent email clients used worldwide, and this error occurs when your Outlook account gets disconnected automatically. Your sent emails get stuck in the Outbox. Even restarting the app doesn’t help here, the email resides stuck in the Outbox.

Unknown error has occurred in Outlook. Outlook Error Code 17884, Mail could not be sent.

Let’s review what causes this Outlook error code 17884 and how we can fix it.

Microsoft outlook error

There can be several different causes for this error which include-

  1. Bad connectivity
  2. Large email attachments.
  3. A problem with the Exchange server
  4. Junk Emails
  5. Daily Limit
  6. Incorrect Email Address
  7. An out-of-date version of Outlook

1. Bad Connectivity

The most common error is lousy connectivity. Intermittent internet connect can automatically disconnect the Outlook account, and your emails will get stuck in the Outbox. In such a case, check your internet connection, restart Outlook, and try sending the email again. Most of the time, it works.

2. Large Attachments

An Email with large attachments might also not get through. With Outlook you can send an attachment of a maximum of 20 MBs, and this is valid for all versions. Your email won’t be delivered if they exceed the allowed attachment limit and may get stuck in the Outbox showing the error 17884.

3. An issue with the Exchange server

Error Code 17884

Check if the outbound server name (SMTP) is correct. To check or change the SMTP settings, go to your Account, click on Server Settings.

4. Junk Emails

You won’t be able to send or receive any emails if your inbox is full. Eliminate the unwanted emails, empty the spam and trash box to get some space, and try sending the email stuck in the Outbox.

An Unknown error has occurred in Outlook

5. Daily Limit

You might have run out of the daily limit. Outlook has a limit of sending 300 emails per day, 30 per minute, and up to 100 recipients per email. This is to avoid email spamming. Check if you have already attained the limit; in such a case, draft your email and send it the next day.

6. Wrong eMail Address

This is a fundamental mistake and a prevalent mistake. Check if you have put the recipient’s email address, even a small comma instead of a dot will not let your email go.

7. Repair Office apps

how to solve outlook Error Code 17884

Go to your PC Settings > Apps & Features and Type Office in the search bar. Click on Microsoft Office and go to the ‘Advanced Settings’ tab. Click on Repair and restart Outlook. This might resolve your problem, and you may send the emails stuck in your Outbox.

8. Obsolete version of Outlook

If none of the above fixes help, uninstall the Outlook app, and install it again, you might be using an obsolete version of Outlook.

The fixes mentioned above will possibly solve your Outlook Error 17884, and you will send the emails again. Do let us know if it’s still not working for you.


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