I did a search on this forum and tried several of the suggestions but non appeared to work. Some email providers (such as your ISP or even Gmail) won't let you send messages larger than a certain size. Adding pictures and large attachments to your message can prevent you from sending that message (and any messages sent inbox repair tool alternative after the large message). If you’re using cPanel, Outlook is most likely setup with POP3 account or IMAP. I’ve seen some providers have issues when auto Send/Receive is set to less than 5mins. Outlook accounts can have up to 100GB of storage per mailbox.

Repair your classic Outlook program

It includes a listing of your accounts, autocomplete information, and your name and initials. To repair your Outlook profile or create a new one, see Fix your Outlook email connection by repairing your profile. Go to your Outbox and then open the stuck email messages. If that message has an attachment that's larger than 20MB, delete the attachment and either attach a smaller file Fix Outlook Not Opening After Windows Update or attach a link to the attachment. For more information, go to Reduce attachment size to send large files with Outlook or Exchange Online limits.

Make sure you are connected to the Internet

For more information, please go to Sync to manually check for new mail and to send messages in Outlook. Sometimes, an Outlook add-in will crash and prevent your email messages from sending. To disable all add-ins, you can start Outlook in safe mode. If you can send email while Outlook is in safe mode, creating a new Outlook email profile should allow you to send email again.

Check your blocked users list

Articles, examples, tutorials, and inspiration from our emailing experts. Create your account and connect with a world of communities. Find solutions to common problems or get help from a support agent. Occasionally, the Outlook program may need to be repaired. Repairing is a simple process but may take as long as half an hour to complete. For more information, see Repair an Office application.

Create a new Profile

But if you’ve never cleaned your inbox, then you might have maxed out your storage limit. So if you’re waiting for an email from someone, you may want to check if the sender is registered on your blocked users list. But still, it’s worth checking if other users are currently experiencing similar issues with Outlook. Microsoft comes with a great option called Work Offline.

• Adding pictures and large attachments to your message can prevent you from sending that message (and any messages sent after the large message).
• This repair should take approximately fifteen minutes.
• To start Outlook in safe mode, press the Windows key on your keyboard.
• I am fairly sure it is something in my Microsoft account since all 4 of my Windows computers stopped working for the email at the same time.
• Microsoft comes with a great option called Work Offline.
• I deleted the Yahoo and Google accounts from Outlook and set it up again and that didn't fix anything.

For more information, visit Add an email Troubleshoot Office 365 Sync and Login Issues account to Outlook for Windows. If that doesn't fix the problem, see the next section. To get help and troubleshoot other Microsoft products and services, enter your problem here.