[Fiddler] Fix "The proxy server isn’t responding" Problem Caused by Fiddler

Very occasionaly I ran into the problem of losing network connection after using Fiddler for debugging with web traffic. To be more precise, this problem usually happens after closing the Fiddler application, and it seems more reporducible when using the FiddlerCore API(However, this is very likely because my code didn't release Fiddler in the correct way...) After this problem happens, and when I open IE, I see the error message of "The proxy server isn't responding" as follow:

This is caused by, as far as I see it, that Fiddler sometimes fails to unregister itself as the system proxy upon on quitting. In that case you will be redirecting all your HTTP traffic to a proxy that doesn't exist, and thus gives you the error shown above.

Easy way to fix this, is to reluanch Fiddler application which will act as system proxy again (make sure you set the option in "Fiddler Options" - "WinINET Connetions"). Close the application gracefully and it should fix the connetion path for you.

Or, you could manually clear the proxy settings by going to Internet Options, select "LAN setting" in "Connections" tab, and uncheck the option of "Use a proxy server for your LAN". (In which you should see a proxy like, which is the default listening port for Fiddler.)

Comments (62)

  1. drew says:

    You just saved me 10 hours of trying to figure this out. thanks

  2. Ram says:

    Thanks for this helpful tip, really saved my time !!!!

  3. sethigh says:

    super like.

  4. Phil Smith says:

    Tyler, I want to kiss you all over and shower you with beer. You have saved me hours and hours.

  5. Chefmar says:

    Thanks so much…worked like a dream

  6. Charles says:

    Spent a good part of an hour to sort this. Just a few clicks from your direction and am back. Thanks

  7. faisal says:

    thnx man ^_^ the scond way is good :*

  8. mark says:

    Dude your freaking awesome thanks a lot!

  9. TJM says:

    Another happy customer. Don't know how it happened. W8 OK then suddenly stopped. Thank you.

  10. Kody says:

    Don't know what fiddler is…  :/

  11. ted says:

    Thanks man, you just saved me from another a week of banging my head against a wall.

  12. marble says:

    great & working tip ! wish you succeed …

  13. jb says:

    Thank you so much saved me so much time hah

  14. drew says:

    back in action thanks to this post!

  15. Matt H says:

    Thank you, you just saved me so much time! I have been borrowing friends laptops and computers the last few weeks to pay bills and manage finances, this has helped so much!

  16. mikey g says:

    i go into internet options and uncheck the box that says use a proxy server, yet when i open the again internet options the proxy server box is ticked!!! it happens every time and i have no idea what to do!!!!

  17. Vivian says:

    Thank you

    All I did was opened fiddler and it worked

    You saved me of a headache

  18. mostafa says:

    really appreciate it. very useful.

  19. Heather kindred says:

    Thank you so so much this just worked for me 🙂

  20. Luis says:

    You are the man!! Thanks fornthe help!

  21. Sean F says:

    Thank you very much Tyler……..you just saved me a lot of aggravation….AWESOME advice AWESOME

    THANKS !!!!!!!!!!!!!!!!!!!!!!!!!!

  22. Jeanette says:

    Another satisfied customer here too! Thank you sooo much!

  23. Gillian Holder says:

    Thank you! Spent hours trying to sort this out

  24. Michael says:

    You saved my life

  25. Lydia says:

    Thank you so very much…..

    Used the last option and it works like a charm.

    Never heard of Fiddler, but whatever the problem was, it's fixed now.

    After hours of frustration, this took about 2 seconds!

  26. T says:

    Thank you! THANK YOU!!! I couldnt believe that it worked and couldn't be soo greatfull for your help as it helped resolve my issue!!! Thank you for curing my headache and for saving me $$$!!!

  27. Terri says:

    THANK YOU!!!!

  28. Joan says:

    Thank you so much!!!!!

  29. Lisa says:

    Thankyou! it works now. You are awesome!!

  30. Rick says:

    Thanks!  Job very well done with why and how to fix.  I ran into this after running Malwarebytes Anti-Malware and your manual fix did the trick.  

  31. Natasha says:




  32. Rene says:

    You are truly awesome! Everyone else recommends a clean install.

  33. Gbrown says:

    Awessssoooommmmmme!!!  Thanks so much.  You saved hours of time!    You are the best!!

  34. JCoffel says:

    Ok, so i followed the steps to manually reset.. once i finished, it still had the same issue.. is there something more that can fix this?

  35. J says:

    Hey, if you are following the manually reset. Once you deselect the option "Use a proxy server for your LAN", in the same window at the top select "Automatically detect settings", and then it should work (at least it works for me)

  36. Chris says:

    Thank you thank you thank you thank u

  37. jessicababer says:

    Unlock our website right now at are house

  38. Darlinda says:

    Thank you! I put the message in the search box and up came this link. Worked like a charm.

  39. casip says:

    Thanks sooooo much

  40. Joanne says:

    Thank Goodness it worked [unchecking the proxy for LAN box.!]

    Thank YOU very much!

  41. Brice says:

    This does not work for me every time I uncheck a box when I go back it changes back.

  42. Brigg says:

    The process works but comes back even in a new tab.i


  43. Knut says:

    I consider myself to be a computer genius.. and have over 30 years of computer experience.  I have been battling with web pages that would not load fast for years.. and it turns out that this one setting posted by Fiddler fixed the problem instantly!  It amazes me that I have software such as Iolo's System Mechanic, Auslogic's BoostSpeed, CleanMyPc, MyCleanPc, and other similar utilities, and all of them find thousands of problems and fix them.. but none of them fixed the problem that needed to be fixed!  

    Thanks Fiddler!

  44. Knut says:

    Whoops.. I made a mistake.. I thanked "Fiddler"  I meant to thank Tyler Fang

  45. Selena says:

    Um….When I uncheck the box like everyone says to do, it gets checked automatically again. How do I stop and fix this?

  46. Big Bob says:

    Tradition, Tradition…

    Fiddler on the Roof

  47. David S. 827 says:

    A support engineer from the MS Community sent me your way, and unfortunately this wasn't much help. I wasn't running Fiddler – hadn't even heard of it until I got the link to here – and have tried umpteen times to reset the proxy sever manually. It refuses to unlatch. Each time I go back it's checked again. The network connections window says I have a connection, but my browser keeps saying "Proxy server isn't responding". I'm guessing I may have to wipe IE and start over, or maybe do the same with Windows.

  48. larissa says:

    I don't even have fiddler but its showing me this error

  49. Kristen says:

    This does not work nothing that anything is saying to do is working i don't know what else to do? Anyone can please help me before I throw this computer

  50. Alicia says:

    Thank u so much!!! It works now 🙂 Soooooo happy ^^

  51. Madhu says:

    Thank you so much.. I've really stopped using IE, Chrome…. It's solved my problem………………. THANKS THANKS THANKS

  52. Rafi says:

    When I uncheck the box for the proxy server and click apply, the setting doesn't change automatically it checks the box again

  53. pat says:

    try all suggestions , nothing works yea!!!!

  54. Yvette says:

    OMG! Thank you. My internet is back!

  55. Jerry says:

    Awesome Fix. Thank you for posting.

  56. vfr2fast says:


    On my Win 8.1 machine, I had malware infection — so I had run malwarebytes and it found 7 serious and 43 other.  Quarantined them all.  Then the "proxy server box ALWAYS stays checked problem/virus/whatever" arrived.  No scanner I used would identify a fix to this problem.

    The only way I was able to correct this was to boot into safe mode w/ networking (had to "bcdedit /set {default} bootmenupolicy legacy" for the F8 option to return), went to internet options/connections and unchecked/applied… it held.  Then when I rebooted into regular mode, internet came back, check stayed off there too.  Hallelujah.

  57. nancy says:

    I tried rebooting in safe mode but when going to internet options in safe mode, it was not on the list. Each time I try to change the proxy settings it will revert back….help!

  58. Lisa says:

    The above "fixes" are good, but it reverts back to the defaults when the computer is shut down.  To fix the problem for good, I do it another way. It works great!

    1. Internet Options

    2. Connections

    3. LAN Advanced Settings (leave the Proxy Server checked to get to the advanced settings).

    4. Manually clear out all the Addresses that the Proxy Server uses.

    5. Click OK.  (If you get an exception "Invalid Proxy Server", click YES).

    You are back to LAN Settings.

    1. Leave the "Automatically Detect Settings" checked.

    2. Uncheck "Automatic Configuration Script".

    3. Uncheck "Use Proxy Server for your LAN Settings"

    4. Check "Bypass Proxy Server for local addresses".

    5. Click OK to the Proxy Server area.

    6. Click OK to Internet Options.

    I never get the proxy server message nor does it reset when the computer is shut down. I had all kinds of problems with the proxy server before I finally figured out how to correct the problem.

  59. Linwood says:

    Thanks, I spent hour with this problem  and you fixed it in 5 minutes.  

  60. Miapaez says:

    Thank you , I fixed this problem with your help.

  61. Shailesh says:

    Thanks .. Tyler . Your suggestion save my lots of time  and help me in solving the problem

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