How to Fix Outlook Not Sending Emails in Outlook 2019 and 2016
Resend the Message
Sometimes trying to send an email again does the trick.
Double-check Recipient’s Email
A tiny typo—such as a comma instead of a period—prevent Outlook from sending an email.
Check Your Connection
Verify you are connected to the internet then ensure you’re working online in Outlook.
Look at Attachments
Outlook limits the size of files you can send to 20 megabytes for internet accounts, such as Gmail or Hotmail, and 10 MB for Exchange accounts. If you receive an error message about the file size when you attempt to send an email, increase the Outlook attachment size limit.
Sync Your Password
If you have recently changed your email password online, you must change it in Outlook as well or you won’t be able to send (or receive) emails.
Repair Outlook
It’s possible your Outlook application is damaged. Use the built-in Microsoft Office repair utility to fix it.
Repair Outlook 2016, 2013 or 2010 in Windows 10
Repair Outlook 2016, 2013 or 2010 in Windows 8
Repair Outlook 2016, 2013 or 2010 in Windows 7
Fix Outlook Not Sending Emails in Outlook for Mac 2016
In the Mac version of Outlook, there are a few things you can try to get Outlook working again.
Double-check Recipient’s Email
A tiny typo, such as a comma instead of a period, can prevent Outlook from sending an email.
Check Your Connection
First, make sure you are connected to the internet. Once you have confirmed your connection, make sure you are working online in Outlook. To do so, go to the Outlook menu, check to see if Work Offline is selected. If so, click Work Offline to remove the check mark and work online.
Empty the Send Folder
Empty the folder to clear “stuck” messages. Any message you delete must be re-created—it cannot be recovered or undeleted.
Rebuild the Outlook Database
Using the Microsoft utility to rebuild a corrupted database might fix Outlook. If you use a Microsoft Exchange account, rebuilding the database will delete any information not synced with the server. Back up any Outlook data stored only on your computer before you rebuild the database.
Fix Outlook Not Sending Emails in Outlook Online
Empty Your Inbox
If your inbox is full, you will not be able to send or receive any messages. Start by deleting any unwanted email messages from the inbox, then right-click Junk Mail and click Empty.
Double-check Recipient’s Email
A tiny typo, such as a comma instead of a period, can prevent Outlook from sending an email.
Try Again Tomorrow or Increase Your Sending Limit
Outlook.com limits the number of emails you can send in a day to deter spammers. If you have recently sent a large number of emails, save the draft and send it the following day. Alternatively, increase your sending limit by updating security settings. Visit the Microsoft Account Security page, click Update Info, verify your identity, then follow the on-screen instructions to update your security settings.
