Are you getting frustrated because sent emails goes to Outbox instead of sending properly. Its a very common problem in Outlook and most of the times it raises due to large file size of attachments (emails).
This type of issue occurs when you found sent message still in the Outbox after clicking on send button. So, why do emails get stuck in outlook Outbox and how to fix it?
Take a look on the actual reasons of message in Outbox and how to troubleshoot these email messages which are stuck in your Outbox. Apart from large attachment there are long lists of causes which can create such disturbance in Microsoft Outlook such as:
Clear Stuck Emails From Outbox: If you found any of email with large attachment or large email which is not able to send and gets stuck in the Outbox, then delete it or reduce its size. To do the following task, you have to first enable the "Work Offline" mod. After moving into different folder/deleting/reducing the email's size disable the "Work Offline", so mails can send again.
To disable the "Work Offline", follow the given path:
File >> Work Offline (Click on it)
Offline Mode: If mail server is offline or you are working offline, then it's obvious that Outlook emails will stay in the Outbox. Enable the working mode into online mode via checking the status bar which exists on the right-down corner of Outlook's window it helps in sending email.
Enable Send/Receive Settings as Automatic: Sometimes while configuration of an account in Outlook we don't much concern on the several basic points like Send/Receive settings. We generally elected it as manually instead of automatically. As result in, the mails will only send or receive when you make a click on the "Send/Receive button" otherwise email goes to Outbox in outlook.
Improper Account settings (with mail server): Sometimes, users find their message in Outbox after sending which can be happen due to the wrong or incorrect account settings and related details like port numbers, SSL/TLS authentication etc. Wrong SMTP (Outgoing server) details is top of the reason in this scenario.
Corruption in SRS File (Send Receive Settings): This file contains all the settings related to send/receive authentication and save them as a .SRS file. A single corruption in SRS file can produce disturbance in sending/ receiving and Outlook mail goes to Outbox instead of sending. To fix this issue, change the name to srs-file to old. The SRS file found on the following path (in Window7 and above versions):
C:\Users\username\AppData\Roaming\Microsoft\Outlook\
Disable the scanning programs (Firewall & Antivirus): Are you using any scanning programs in the system? And outlook emails not sending. They are going directly to Outbox, then surely you should check (disable) the settings of scanning programs such as firewall and antivirus softwares.
Delete the Corrupted Outbox: Though Outbox can also corrupt and if it has been corrupted then Outlook's email directly go into Outbox. Now question is that "How to fix stuck email in Outbox". In this instance, first go to Outbox and change the status of important emails to drafts by opening and closing them. Now, turn off the Microsoft Outlook and find out the "Outbox.dbx" by implementing system file search and delete the file. Close Outlook and restart it, after turning on MS-Outlook everything will be fine and you can send the drafted emails properly.
There are lots of numerical errors which point out while sending email and therefore outlook emails stay in Outbox. And these numerical errors transform into the corruption of Outlook PST Data File. Most of the users also face similar Outlook problems where they found email stuck in their Outbox. But it's an extreme confusing situation when an Outlook user sent the message and its still in Outbox and next he/she is looking answer for the query "how to troubleshoot email messages that are stuck in your Outbox".
After failing all the techniques or methods from the above given terms, there is only one prominent which is excellent technology to fix the every type of corruption problems in Outlook known as Outlook Recovery tool.