The good news is that most of these Outlook Express mail sending problems can easily be fixed. At times, even corrupt PST files can cause these unwanted Outlook-related issues. Other Reasons: Besides that, Outlook might not be able to send emails if your system is not connected to a stable network or the file could be used by any other program. Firewall Issue: The installed anti-virus or firewall on your system could have blocked a vital port or component that that is needed by Outlook to send emails.ĥ. Authentication Error: The problem can also be caused if the authentication or security settings (or SSL/TSL certifications) have been expired or are wrongly configured.Ĥ. Therefore, if your email has crossed the limit, then Outlook won’t be able to send it.ģ. Large Email Attachment: By default, Outlook has a limit of 20 MB for the size of any email attachment. Wrong Configuration: If your Outlook account has not been configured properly or you have entered the wrong IMAP/POP/SMTP details, then it can cause this issue.Ģ. Before we diagnose the problem, let’s have a look at some of its leading causes:ġ. Ideally, there could be all kinds of Outlook Express mail sending problems causing this issue. Many factors contribute to your outlook not sending emails from the outbox. You might see queries like 'error messages' after you attempt to send a message. When messages get trapped in outlook, the messages take a lot of time during sending and might eventually return unsent. So you probably are not the only one reading this article and it likes presently. However, when i install Office 365 on any new Windows 10 PC's, I am unable to roll back the update as no previous updates are installed and installing old updates manually is proving to be more difficult than anticipated.Why Do Emails Go To Outbox But Not Sending?įor many outlook users mail not sending and getting jammed in the outbox is a very common thing.

I tried it out and the problem was immediately resolved on all of our current Windows 10 systems.

I found a conversation with Google support reps that said they have received numerous support tickets regarding this issue and suggested a way to roll back the version of Outlook 365 to the previous monthly update and then disable further updates. Any emails they create and send go to the outbox but never get sent out and there are no sync error messages from GSync. They all use company owned Gmail accounts and connect to their gmail accounts in Outlook by using G Sync. I have a large number of users who were unable to send emails after the April update to Outlook 365 was installed on their systems and I have not been able to find any relevant discussions on this topic here.

Outlook mail stuck in outbox office 365