Outlook and Proxy Server Issues

Outlook Not Syncing

• 1. Run PST/OST repair
Scanpst.exe is located in various locations depending on the version of Microsoft Office being used. Run scanpst.exe as administrator, locate and select the *.ost or *.pst file to repair. After scanpst.exe has repaired the ost/pst file, repeat the process on each ost/pst file as needed.
• 2. Run Online Repair of MS Office from Apps and Features
In Windows 10/11 right click on the Windows icon, and select Programs and Features.
Scroll to Microsoft Office and select Modify. Then select Online Repair.
• 3. Run Repair in Email Accounts in Outlook from Programs and Features
In Search type Control and select Control Panel. In the control panel select email or Outlook.
Select Accounts, select the account to be repaired and select repair. Run repair as needed on each account.
• 4. Run chkdsk /f
Various versions of Windows has either cmd, PowerShell or Terminal. Open one of these as administrator. I prefer using the command chkdsk /f but sfc /scannow can be used. Follow the prompts accordingly.

Outlook Proxy Error 80000000
Regedit HKLM\WOW6432Node\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp
DefaultSecureProtocols value a00

Run either cmd, PowerShell or Terminal as administrator.
Run DISM /Online /Cleanup-Image /RestoreHealth
Note, this will take some time so be patient; I have seen it complete in five minutes, in one case it took several hours.
After running the DISM Restart the computer.

Resolve Proxy errors

• 1. RegEdit HKCU\Software\Software\Microsoft\Windows\CurrentVersion\Internet Settings delete ProxyEnable

For Proxy Server Not turning off:

• 1b. Regedit HKLM\SOFTWARE\Policies\Microsoft\Windows\CurrentVersion\Internet Settings add NEW DWord 32bit, name it ProxySettingsPerUser, with Value data 1, click ok
• 1c. Open cmd as administrator run netstat -abno | findstr LISTENING | findstr :8080 if a program results open task manager and End that task, and try to change proxy settings again


• 2. cmd as administrator ipconfig /flushdns
• 3. cmd as administrator nbtstat -r
• 4. cmd as administrator netsh int ip reset
• 5. cmd as administrator netsh winsock reset
• 6. disble Proxy Server Windows+I, choose Network & Internet, Select Proxy, select Manual proxy setup edit, turn proxy server off and click save
• 7. Windows+I, choose Network & Internet, select Advanced Network Settings, select Network Reset, select reset now
• 8. Restart Computer
• 9. Reset browser (Chrome) open settings, select advanced, select Reset and Cleanup, choose restore to original defaults, select reset settings, close Chrome
• 10. Run malware scan
• 11. Disable proxy LAN settings, Windows+R type inetcpl.cpl, open Connections tab, select LAN settings, click ok, in Proxy server uncheck use proxy server for LAN, click ok, click ok in Internet properties
• 12. Open Device Manager, in Network Adapters right click and uninstall your network device
• 13. Restart computer and open device manager, scan for hardware changes, download and install any needed drivers

Primary Proxy Server Error Codes

• 400- Bad Request: Invalid client request.
• 401- Unauthorized error: This error occurs when a server cannot authenticate the request. Run cmd as administrator ipconfig /flushdns, and clear the browser history.
• 404. Object Not Found - what you are looking for is no longer there.
• 407. Proxy Authentication Required - you have not entered the correct credentials, or the server does not recognize the authentication you used.
• 429. Too many requests - you or the computer has tried too many times.

Reset WinHTTP Proxy Server Settings in Windows 11/10

• 1. Run cmd as administrator netsh winhttp reset proxy
• 2. In Chrome browser enter chrome://net-internals/#proxy
• 2b In Firefox browser enter about:preferences#advanced scroll down and click Network Proxy Settings button
• 3. RegEdit HKCU\Software\Software\Microsoft\Windows\CurrentVersion\Internet Settings ProxyEnable 0 disables, 1 endables
• 4. Run PowerShell as administrator Get-ItemProperty -Path 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Internet Settings' | findstr ProxyServer
• 5. Run PowerShell as administrator netsh winhttp reset proxy will remove a proxy server and configure direct access to the internet