This guide will show you How to Fix Microsoft Outlook Error 0x800ccc15. When you attempt to send or receive email, you see one of the following error messages. The message could not be sent to the SMTP server. The transport error code was 0x800ccc15.

RECOMMENDED: Fix this issue in 3 simple steps. Takes only 2 minutes.
1) Download repair utility.
2) Install program and click Scan button.
3) Click Fix Errors button when scan is completed.
4) Restart your computer.

This issue may occur if one of the following scenarios is true:

Your Outlook might be disconnected or not connected to Internet.
Incorrect settings of Outlook mail account.
Incomplete installation of Outlook
Incorrect configuration of Antivirus software
When your Outlook user profile is damaged.
Corrupt or damaged PST files
If Outlook email item on your POP3 server is damaged.
When Outlook is removed or installation of Outlook is damaged.
This occurs when port 25 is blocked by ISP.

Warning : Before making any changes in your computer, I suggest you to create a System Restore point so that you can restore back your computer to previous working stat if something goes wrong.

How to Fix Microsoft Outlook Error 0x800ccc15

Step 1: Make sure that your Outlook email account settings are correct.

We recommend that you contact your Internet service provider (ISP) for information about the exact incoming and outgoing mail server names and settings that you should use when you configure your Internet email account in Outlook. The list provided here contains information only for some Internet service providers in the United States and may not be up to date.

Incoming Mail (POP3) server names and settings:

Provider Name	Server Name	Port	SPA	SSL	AuthRequird
AOL	pop.aol	110	OFF	OFF	ON
AT&T Yahoo	pop.att.yahoo.com	995	OFF	ON	ON
Charter	pop.charter.net	110	OFF	OFF	ON
Comcast	mail.comcast.net	995	OFF	ON	ON
Cox	pop.[insert region].cox.net	110	OFF	OFF	OFF
Gmail	pop.gmail.com	995	OFF	ON	ON
Juno	pop.juno.com	110	OFF	OFF	OFF
Microsoft Live	pop3.live.com	995	OFF	ON	ON
Netscape	pop.3.isp.netscape.com	110	OFF	OFF	ON
Netzero	pop.netzero.com	110	OFF	OFF	ON
Pacbell	pop.att.yahoo.com	995	OFF	ON	ON
PeoplePC	pop.peoplepc.com	110	OFF	OFF	ON
Qwest	pop.[enter state ID].qwest.net	110	OFF	OFF	OFF
Rogers	pop.broadband.rogers.com	110	OFF	OFF	ON
SBCGlobal	pop.att.yahoo.com	995	OFF	ON	ON
Swbell	pop.att.yahoo.com	995	OFF	ON	ON
Verizon	incoming.verizon.net	110	OFF	OFF	ON
Yahoo	pop.mail.yahoo.com	110	OFF	OFF	OFF

Outgoing Mail (SMTP) server names and settings:

Provider Name	Server Name	Port	SPA	AuthRequired	Encryption
AOL	smtp.aol.com	587	OFF	ON	None
AT&T Yahoo	smtp.att.yahoo.com	465	OFF	ON	SSL
Charter	smtp.charter.net	25	OFF	ON	None
Comcast	smtp.comcast.net	587	OFF	ON	TLS
Cox	smtp.[insert region].cox.net	25	OFF	OFF	None
Gmail	smtp.gmail.com	587	OFF	ON	TLS
Juno	authsmtp.juno.com	587	OFF	OFF	None
Microsoft Live	smtp.live.com	587	OFF	ON	TLS
Netscape	smtp.isp.netscape.com	25	OFF	OFF	None
Netzero	authsmtp.netzero.com	25	OFF	ON	None
Pacbell	smtp.att.yahoo.com	465	OFF	ON	SSL
PeoplePC	smtpauth.peoplepc.com	587	OFF	ON	None
Qwest	pop.[enter state ID].qwest.net	25	OFF	OFF	None
Rogers	smtp.broadband.rogers.com	587	OFF	ON	None
SBCGlobal	smtp.att.yahoo.com	465	OFF	ON	SSL
Swbell	smtp.att.yahoo.com	465	OFF	ON	SSL
Verizon	outgoing.verizon.net	25	OFF	ON	None
Yahoo	smtp.mail.yahoo.com	25	OFF	OFF	None

Step 2: Check your antivirus manufacturer’s website for additional suggestions or Disable the antivirus software. And Disable the firewall in router.

If you found outlook is working fine after disable the antivirus software, highly recommended to uninstall the same using their removal tool and reinstall it.

List of manual antivirus uninstallers

Click the link associated with the antivirus software currently installed on your system and follow the prompts or instructions on the website.
Once uninstallation is complete, you will need to restart your computer.

Avast	http://www.avast.com/uninstall-utility
AVG	http://www.avg.com/us-en/utilities
Avira	http://www.avira.com/en/support-for-free-knowledgebase-detail/kbid/88
BitDefender	http://kb.bitdefender.com/site/article/333/
BullGuard	http://www.bullguard.com/support/product-guides/bullguard-internet-security-guides-12/getting-started/uninstalling-bullguard.aspx
CA Antivirus	see Total Defense Anti-Virus
Comodo Internet Security	https://support.comodo.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=298
CounterSpy	http://www.google.com/#q=counterspy+uninstall
Cyber Defender Early Detection Center	http://www.ustechsupport.com/faq.html#q4
Dr. Web	https://support.drweb.com/support_wizard/?lng=en
Dr. Web	(Only registered Dr. Web users can access support content)
eScan	http://www.microworldsystems.com/download/tools/esremove.exe
ESET	http://kb.eset.com/esetkb/index?page=content&id=SOLN2788
FRISK F-PROT Antivirus for Windows	http://www.f-prot.com/support/windows/fpwin_faq/25.html
F-Secure	ftp://ftp.f-secure.com/support/tools/uitool/UninstallationTool.zip
F-Secure	http://community.f-secure.com/t5/Security-for-PC/How-do-I-uninstall-the-product/ta-p/15384
G Data	https://www.gdatasoftware.co.uk/?eID=PushFile&dl=f4b2f2fd23%3AAFEIBgU%3D
Kaspersky	http://support.kaspersky.com/common/service.aspx?el=1464
K7 Total Security	http://www.k7computing.com/en/tools/K7RT.exe
LavaSoft	http://www.lavasoftsupport.com/index.php?showtopic=28
Malwarebytes	http://www.malwarebytes.org/mbam-clean.exe
McAfee	http://download.mcafee.com/products/licensed/cust_support_patches/MCPR.exe
Microsoft Security Essentials	http://support.microsoft.com/kb/2435760
Norman Virus Control/Norman Security Suite	http://www.norman.com/support/support_issue_archive/67798/en
Norton (Symantec)	ftp://ftp.symantec.com/public/english_us_canada/removal_tools/Norton_Removal_Tool.exe
Norton Security Scan	ftp://ftp.symantec.com/public/english_us_canada/removal_tools/NSSRT.exe
Panda	http://www.pandasecurity.com/resources/sop/UNINSTALLER_08.exe
Panda Cloud Internet Protection	http://www.pandasecurity.com/resources/sop/Cloud_AV_Uninstaller.exe
Pareto Logic	http://www.paretologic.com/resources/help/xoftspyse/195.htm
Sophos	http://www.sophos.com/support/knowledgebase/article/11019.html
Spybot Search & Destroy	http://www.safer-networking.org/faq/how-to-uninstall-2/
Total Defense Anti-Virus (formerly CA Anti-Virus)	http://totaldefense.iyogi.com/?p=368
Trend Micro	http://esupport.trendmicro.com/solution/en-us/1056551.aspx
Trend Micro Titanium	http://esupport.trendmicro.com/solution/en-us/1059018.aspx
Trend Micro Worry-Free Business Security Agent	http://esupport.trendmicro.com/solution/en-us/1057237.aspx
Vipre (Sunbelt Software)	http://kb.threattracksecurity.com/articles/SkyNet_Article/How-to-Uninstall-VIPRE-Antivirus-and-VIPRE-Internet-Security
Webroot	http://www.webroot.com/prodCheck/?pc=64150&origrc=1&oc=221&mjv=7&mnv=0&rel=6&bld=38&lang=en&loc=AUS&kc=ppc%60lkik^^afhgpewgfa&opi=2&omj=6&omn=1&osl=en&errid
Windows Defender	http://kb.eset.com/esetkb/index?page=content&id=SOLN2390
Windows Live OneCare	http://download.microsoft.com/download/4/c/b/4cb845e7-1076-437b-852a-7842a8ab13c8/OneCareCleanUp.exe
Windows Security Essentials	http://support.microsoft.com/kb/2435760
Zone Alarm	http://download.zonealarm.com/bin/free/support/download/clean.exe

Step 3: Create a new E-mail profile.

Conclusion:

If above steps did not help you to resolve the issues, you may have to create new outlook profile and reconfigure email settings, try creating new Windows user account as well. Hope this will help you to fix the issues. Or you have to contact your ISP for further assistance. For further support, leave comments or ask more on Forum.