0x800ccc0f error outlook 2019 - works wired, error wireless

I had exactly the same problem. Outlook 365 on two different accounts was giving me a 0x800ccc0f error when sending HTML messages wirelessly. (Never tried to send over a wire.) All the hints and suggestions in Windows and Google say the problem is related to a conflict with your firewall. So I disabled/uninstalled McAfee. Nope. Changed Outlook profiles. Uninstalled/reinstalled Office. I spent hours trying to fix this problem. Finally completely reset Windows 10 hoping the bloatware wouldn't be reinstalled. No such luck. Must be part of the Dell version of Windows.

So I deleted McAfee. Installed all Win updates. Installed Office 365. Installed Office updates. Configured my two accounts in Outlook. Immediately had the same problem.

So I continued to Google the problem over and over. Finally found a single reference on a Windows tech site (thank you Wiiindy, whoever you are) that said SmartByte was the problem. Disabled the service and my emails started flying out. Re-started the service and the problem came back. 

Lots of references to the fact that this software won't go away. So I disabled it in Windows versus trying to uninstall it. Everything is now working great. I actually really like this Dell (Inspiron 13 7000 2-in-1). But I can't stand the problems that are created by software I didn't ask for and can't get rid of...even when doing a Windows 10 reset.

We apologize for the issue that you have experienced!

The most recent version of SmartByte should not have this issue, but we certainly want to know if you are seeing this problem with the current version! You can check your installed version by searching SmartByte in Windows Search, then clicking the SmartByte App. Once you have SmartByte open, press F4, and look for the version number on the bottom. The version number should be at least version 2.0.613. If it is not, try updating from Dell here - 

<ADMIN NOTE: Broken link has been removed from this post by Dell>

If you are still experiencing problems on the current version of SmartByte, please contact us directly at killersupport@rivetnetworks.com so that we can better help you!

-- Anthony with SmartByte Support and Killer Networking

Is the problem that we have experienced a "known" problem with some versions of SmartByte?

Why did this problem occur with Outlook and not Thunderbird?

There were some situations where changes to Windows 10 caused issues with older versions of SmartByte, as we have corrected these issues with the current version. I couldn't say why the issue may have affected Outlook and not Thunderbird. It's likely that the changes in the operating system primarily affected Microsoft applications and their connectivity, but that's an educated guess. 

-- Anthony with SmartByte Support and Killer Networking

I know the original post was mine, and apologise for my silence, but I think Dilbertdad summed this up better than I ever could have. The problem was fixed with an uninstall. I cannot think of a motive to install latest version.

Dell does not make outlook or office Microsoft Does.
Microsoft also forces vendors to only distribute the latest version of the software.

The error "unexpectedly terminated" is usually caused by interference from an antivirus program.

Error ID: 0x800CCC0F
Protocol: SMTP
Port: 25
Secure SSL: No

Third-party products that are known to cause this problem include the following:

Market score Net set ter Internet Accelerator
Net Nanny
Panic ware Pop Up Stopper

If the error message is accompanied by a time-out error message, you may be able to resolve this problem
by increasing the server time-out setting in Outlook.
To increase the server time out setting, use one of the following methods.
Outlook 2010 and later

Start Outlook.
On the Files menu, click Info.
Click Account Settings, and then select Account Settings from the list.
Click to select the target POP3 account, and then click Change.
Click More Settings.
Click the Advanced tab.
Gradually increase the server time out setting until the issue is resolved.

---

@speedstep wrote:

The error "unexpectedly terminated" is usually caused by interference from an antivirus program.

Third-party products that are known to cause this problem include the following:

Market score Net set ter Internet Accelerator
Net Nanny
Panic ware Pop Up Stopper

Clearly you didn't read this thread!

The problem was caused by software supplied by Dell and came installed on these laptops.

The issue only showed up on Outlook, however it does mean there were other applications that could have been impacted by this faulty software.

Thank you for sharing this!

Wasted more time on this foolishness than I want to admit... :Angry:

I have a brand new out of the box Dell G7 laptop. I installed my office software and configured outlook exactly like my old laptop with respects to the account and server setting. I was able to receive email with no issues; however, any email I tried to send would just sit in my outbox.

One message post i read indicated that the Killer Control Center may be the issue; however, on my laptop that interface is only for the physical Ethernet connection vs the wifi interface. Since my Ethernet was disconnected, nothing appeared in the KCC when I opened the application. Because of that, I decided to plug my laptop into my home router to see if the KCC program would populate and that is when i saw the emails sitting in my outbox go out.

Seeing this happened helped me narrow down my search which is what allowed me to find this page. I stopped and disabed SmartBytes and I can now send email again when I am using wifi.

Thank you for passing on the fix for this.

Thank goodness for this post. My outlook 2016 desktop app (as part of MS office that I bought with my 3 month old dell inspiron notebook) suddenly quit sending emails, error code as you indicated in the post. I could receive but not send (all accounts). Up to today, no problem. I performed all of the steps Microsoft has online for this error, but no luck. I finally called Microsoft support, ending up having to pay $29 for them to work on it (just out of warranty period). 3 hours later, no luck finding the problem. They escalated it to their level 2 support with a scheduled time next week to work on it.

After MS was done today, I found this post. I uninstalled smartbyte in settings-apps and now my outlook desktop app works again. Clearly, removing smartbyte fixed the problem. No idea why it appeared suddenly.

Thank you so much for this very useful post! My six week old laptop suddenly stopped sending emails today. After trying several things, I stumbled on your post.  I really appreciate you sharing this information and saving me hours of work.