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If you recently installed a Windows update or an Outlook update and suddenly noticed email not sending in Outlook, you’re definitely not the only one. Many home users open Outlook to send an important message only to find it sitting in the Outbox, refusing to move. Outlook may look normal, but something silently blocks the sending process in the background.
Outlook updates often reset account settings, break the connection with your email server, or corrupt parts of your Outlook profile. These hidden issues make it impossible to send an email, even if everything appears fine on the surface. Fortunately, you can fix it with a few practical steps that Microsoft rarely explains clearly.
This guide walks you through every solution in a simple, human-friendly way no technical jargon. If you can follow basic instructions, you can fix your Outlook issue today.
Why Outlook Suddenly Stops Sending Emails After an Update
Most people assume updates improve things, but in reality, a big update can disrupt how Outlook works. The problem usually appears right after a Windows restart or an unexpected Outlook refresh.
Below are the most common reasons emails in Outlook fail to send after an update:
1. Outlook Account Settings Were Altered
Updates sometimes adjust your email account settings, especially outgoing server (SMTP) details.
If the SMTP port or authentication changes even slightly, your email not sending issue begins instantly.
2. Corrupted Outlook Profile
Corruption sounds dramatic, but in Outlook it’s very common. Your Outlook profile stores your mail data, login info, and sync settings. When files inside the profile break, your email message cannot leave the Outbox.
A corrupt Outlook profile can also cause issues with receiving emails.
3. Outlook Add-ins Stop Working
Plugins like calendar extensions, antivirus email scanners, or older add-ins can clash with a new version of Outlook.
Once an add-in fails, it can interrupt the sending process without showing a clear error message.
4. Your Internet Connection Dropped
Sometimes, the issue is not Outlook at all. A weak or unstable internet connection can force Outlook offline, blocking your send or receive actions.
Even a few seconds of interruption can stop an email mid-send.
5. Large Attachments
Many home users attach large images or documents without realizing their email provider limits outgoing email size. When you try sending something above 25 MB, it may get stuck in the Outbox.
6. Mail Server Temporary Block
Your mail server may block your account temporarily due to:
- failed password attempts
- suspicious logins
- inbox limits
- SMTP congestion
This is more common than people realize.
7. Microsoft Glitch After Update
Sometimes, a patch simply breaks something.
The new Outlook, Outlook 2016, Outlook 365, and Outlook for Mac all behave differently after updates. A feature that worked yesterday may suddenly stop working today.
Now that you know the causes, let’s walk through practical fixes that truly work, the ones users wish Microsoft support explained more clearly.
Common Outlook Sending Errors After an Update and What They Actually Mean
| Outlook Error Message | What It Means | How It Affects Sending Emails | User-Friendly Explanation |
|---|---|---|---|
| “Cannot connect to server” | Outlook lost access to your mail server after the update | Emails stay in the Outbox until the connection is restored | Usually caused by internet interruptions or server downtime |
| “Authentication failed” | Your password or login token has changed | Outlook blocks sending to protect your account | Happens often after Microsoft account password resets |
| “Server timed out” | Outlook waited too long for a response | Outgoing emails may fail repeatedly | Common on slow connections or congested servers |
| “Message stuck in Outbox” | The message could not sync with the server | Prevents all other emails from being sent | Often triggered by large attachments or corrupt drafts |
| “0x800CCC0E” | SMTP settings were altered during the update | Outlook cannot send mail due to the wrong port or encryption | Rarely explained by Microsoft, but very common after major updates |
| “Outlook is not responding” | Add-ins or profile data became corrupted | Outlook may freeze before sending emails | Happens when old add-ins are incompatible with the new Outlook |
| “Something went wrong” | General sync error without detailed info | Sends half-completed requests and then stops | Typical when updating from Outlook 2016 to Outlook 365 |
| “Send/Receive error” | Outlook cannot complete the sync cycle | Emails fail to leave the Outbox | Indicates deeper profile or PST issues |
Step-by-Step Fixes for Email Not Sending in Outlook After an Update
These methods are meant for home users, remote workers, and anyone who simply needs Outlook to send their emails again without diving into complex terminology.
Go step by step. One of these will almost certainly fix the problem.
Step 1: Make Sure Outlook Isn’t Working Offline
Outlook sometimes switches to “Work Offline” mode after an update.
To check:
- Open Outlook
- Click the Send/Receive tab
- Look for “Work Offline”
- If it is highlighted, click it again
Once Outlook reconnects, the emails stuck in the Outbox may start sending automatically.
Step 2: Check Your Internet Connection
Before anything else, make sure you are connected to the internet.
If your connection drops, Outlook cannot connect to your email server to send outgoing messages.
Do this:
- Open your browser
- Visit any website
- If the page doesn’t load, restart your router
- Try sending your email again
Many users skip this step only to discover the issue was simple.
Step 3: Restart Outlook Completely
This isn’t just closing the window.
- Close Outlook
- Wait 10 seconds
- Reopen the Outlook application
This forces Outlook to re-establish a fresh connection with your mail server.
Step 4: Clear Your Outbox Folder
A large attachment or incomplete message may freeze the entire sending process.
- Go to your Outbox folder
- Delete or move the stuck email
- Recreate the email with a smaller attachment
If Outlook freezes when you open the Outbox, switch to Outlook in Safe Mode first:
Windows Key + R Type: outlook.exe /safe
Once in Safe Mode, you can delete the blocked message.
Step 5: Verify Your Email Account Settings
Updates occasionally rewrite outgoing server settings.
Do this:
- Go to File > Account Settings
- Choose Account Settings
- Select your Outlook account
- Click Change
- Select More Settings
- Open the Outgoing Server tab
- Ensure authentication is enabled
- Check SMTP port (usually 587 or 465)
If the wrong port is selected, your emails won’t send (and Outlook will not always show a clear sending error).
This is one of the most effective ways to fix Outlook after updates.
Step 6: Start Outlook in Safe Mode to Disable Faulty Add-ins
If you can send emails in Outlook while Safe Mode is enabled, then a faulty add-in is the cause.
To disable add-ins:
- Open Outlook normally
- Click File > Options
- Choose Add-ins
- Click COM Add-ins > Go
- Uncheck all add-ins
- Restart Outlook
Then send a test email.
If it works… the culprit was an add-in.
Step 7: Repair Your Outlook Profile
When updates corrupt a profile, Outlook cannot communicate with your email server.
To repair:
- Go to File > Account Settings
- Choose your email account
- Click Repair
This simple repair fixes many outlook issues, including:
- sync problems
- messages blocking
- authentication errors
- emails stuck in your Outbox
Step 8: Create a Brand New Outlook Profile
If repair doesn’t work, a fresh profile almost always fixes the issue.
Do this:
- Open Control Panel
- Search for Mail
- Click Show Profiles
- Choose Add
- Create a new profile
- Set it as default
A clean profile eliminates:
- corrupt Outlook files
- broken sync settings
- problematic rules
- old configurations
This is extremely effective for outlook not sending emails after major updates.
Step 9: Run an Online Repair of Microsoft Office
Sometimes the Outlook program itself is damaged.
To repair:
- Open Control Panel
- Go to Programs & Features
- Find Microsoft Office
- Select Online Repair
This rebuilds the entire Outlook program, fixing:
- corrupt Outlook data
- broken functionality
- library errors
- issues that prevent emails from being sent
Step 10: Check for Email Server Issues
Your email provider or email server may be temporarily blocking sending due to:
- incorrect password
- failed login attempts
- security lockouts
- mailbox storage full
If you recently changed your Microsoft account password, Outlook may still be using your old one.
Update it here:
File > Account Settings > Email Account > Change
Then test sending again.
Prevent Outlook Email Issues in the Future
To avoid email not sending in Outlook problems again, do the following:
- Restart Outlook once a week
- Avoid oversized attachments
- Clean your Outbox often
- Remove unused add-ins
- Keep Windows and Outlook updated
- Keep your mailbox cleaned and organized
These simple habits make Outlook faster and more reliable.
When to Get Expert Help
If you have tried everything and:
- Your emails are stuck
- Outlook freezes
- Your Outlook profile won’t repair
- You can’t send or receive
- Outlook won’t open
- The error keeps returning
Then you may have deeper issues like:
- corrupt OST/PST files
- broken registry connections
- advanced sync failures
- mail server authentication errors
- damaged local Outlook database
This requires professional support.
Fast, Reliable Outlook Help from OneClick Technologies LLC
If your email not sending in Outlook problem is still happening after trying all the steps above, don’t get stuck wasting hours trying random fixes.
OneClick Technologies LLC provides expert, remote-only IT support tailored for home users and non-technical individuals.
Our trained technicians can fix:
✔ Outlook not sending or receiving
✔ Emails stuck in Outbox
✔ Sync and mail server issues
✔ Broken Outlook profiles
✔ Microsoft account problems
✔ Outlook freezing or crashing
We offer fast, friendly, efficient remote support across the U.S., designed around simplicity and trust.
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