Outlook Error Code 17884, Unknown error has occurred in Outlook

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

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

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

Fix Outlook Error Code 17884

There can be many different reasons for this error which include-

1. Bad connectivity
2. Large email attachments.
3. An issue with the Exchange server
4. Junk Emails
5. Daily Limit
6. Wrong E-Mail Address
7. Obsolete version of Outlook

Unknown error has occurred in Outlook

1] Bad Connectivity

The most common error is bad 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 E-mail 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

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 E-Mails

If your inbox is full, you won’t be able to send or receive emails. Delete unwanted emails, empty the spam and trash box to free up space, and try sending the email stuck in the Outbox.

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 reached the limit, in such a case, draft your email and send it the next day.

Related read: Email in Outlook not syncing in Windows.

6] Wrong eMail Address

This is a very basic and common mistake. Check if you have included the recipient’s email address. Even a small comma instead of a dot will not let your email go.

7] Repair Office apps

Go to your PC SettingsàApps & 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 solve your problem and you may be able to 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 above-mentioned fixes may solve your Outlook Error 17884, and you will be able to send emails again. Do let us know if it’s still not working.