Why is my email stuck in the outbox?
A message that will not go, and often blocks everything behind it. The one test that separates your email program from your email provider, and the attachment problem that causes most of it.
- Difficulty
- beginner
- Time
- 20 min
- Read
- 5 min
Short answer
Sign into your email through a web browser and send a test message from there. If webmail sends fine, the problem is your email program or its connection, not your account — and the usual cause is one oversized message at the front of the queue holding everything up. Move the stuck message to Drafts, which releases the rest immediately, then deal with it separately.
An outbox is a queue, and a queue has a front. That single fact explains most of this fault: one message that cannot be sent — usually because an attachment exceeds the provider's limit — sits at the front and everything behind it waits. Nothing tells you this. What you see is a program that has stopped sending, and the natural response is to check settings that were working perfectly yesterday. The second most common cause is even simpler: the program has been switched to working offline, often by accident, and it is doing exactly what it was told.
Step by step
- Send a test message from webmail first.Sign into your provider's website and send yourself something. This splits the problem in half. Webmail working means the account and the provider are fine, and the fault is your program or its connection. Webmail failing too means the account is the problem — a full mailbox, a suspension, or a provider fault.
- Check whether the program is working offline.Outlook has a Work Offline toggle in the Send and Receive ribbon, and it is easy to press by accident. Other programs have equivalents. A program in offline mode queues everything silently and looks completely normal otherwise.
- Look at the size of the message at the front of the queue.Most providers cap a message at somewhere around twenty to twenty-five megabytes including the attachment's encoding overhead, which adds roughly a third. A photo or two from a modern phone can exceed it. The message will retry forever and block everything behind it.
- Move the stuck message to Drafts.This releases the queue at once and lets everything else go. Then reopen it from Drafts, remove the large attachment, and send the file another way — the catalogue's guide on sending a file too big to email covers the options.
- Check the mailbox is not full.A full mailbox stops sending as well as receiving on many providers, because the sent copy cannot be stored. This is common on old accounts with years of large attachments, and the catalogue has a guide on freeing up email storage.
- Check for an expired password.A password changed on the website, or an account where two-factor authentication was enabled, leaves the program with credentials that no longer work. Some programs prompt clearly and some just fail quietly. An account with two-factor on often needs an app-specific password rather than your normal one.
- Test with security software temporarily disabled.Some antivirus products scan outgoing mail and can break it after their own update. Turning that specific feature off for five minutes is a legitimate test, and if it fixes it, the fix is in the security software's settings rather than in your email program.
- Verify the outgoing server settings only after the above.Settings that worked yesterday rarely change on their own, so this is near the end rather than the beginning. If you do check, compare them against your provider's published values, particularly the port and the encryption setting, which providers occasionally do change.
Common mistakes
- Deleting and rewriting the message — If the cause is an oversized attachment, the rewrite will do exactly the same thing. Find out why it failed first, and check the attachment size.
- Removing and re-adding the account — On some programs this deletes locally stored mail that exists nowhere else, particularly on old accounts set up to download and remove from the server. It is a genuinely risky step and almost never the fix.
- Changing server settings without noting what they were — The settings were working. Changing them turns one fault into two. Write them down before touching anything, if you touch them at all.
If it doesn't work
One message stuck, everything behind it waiting
Cause: That message cannot be sent — Fix: Move it to Drafts. The rest go immediately. This is the single most common shape of this fault.
Nothing sends and nothing receives
Cause: Offline mode, no connection, or the account — Fix: Check the offline toggle first, then whether the machine has internet, then webmail.
Sends from the phone but not the computer
Cause: The computer's program or credentials — Fix: The account is proven fine. Focus on the program: offline mode, password, security software.
Message with a large attachment retries endlessly
Cause: It exceeds the provider's size limit — Fix: Remove the attachment and share the file by a link instead. Note that the encoding overhead means the effective limit is smaller than the stated one.
Started after enabling two-factor authentication
Cause: The program needs a different credential — Fix: Generate an app-specific password in the account's security settings, or switch the account to modern authentication if the program supports it.
Sends but the recipient never gets it
Cause: A different fault entirely — Fix: That is a delivery problem, not a sending problem. Check the sent folder, then look at whether the recipient's provider rejected it — a bounce message usually explains why.
Questions people ask
How big can an email attachment actually be?
Most providers cap a message at around twenty to twenty-five megabytes, but attachments are encoded for transmission and that inflates them by roughly a third — so a twenty-megabyte file can exceed a twenty-five-megabyte limit. Both the sender's and the recipient's provider apply their own limits, and the smaller one wins.
Why does my phone send it and my laptop cannot?
Usually because the phone is using the provider's own app or a different connection, and the laptop is using a program with its own settings, its own stored password and its own security software. That difference is a useful diagnostic in itself.
What is an app-specific password?
A single-purpose password generated in your account's security settings for one program that cannot handle two-factor authentication. It is used once when setting the program up and can be revoked without changing your main password. Google, Apple and Microsoft all offer them.
Should I just use webmail?
For occasional use it is entirely reasonable and removes this whole class of problem. A dedicated program is better for multiple accounts, offline access and large archives. If you find yourself troubleshooting a program regularly, webmail is a legitimate simplification.