47

Error:

[Fiddler] The connection to '<the site>.com' failed. 
System.Security.SecurityException Failed to negotiate HTTPS connection with server.fiddler.network.https> HTTPS handshake to <the site>.com (for #3) failed. System.IO.IOException Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. < An existing connection was forcibly closed by the remote host

I can hit fine in web browser. I do see it is rather strong SSL (FireFox reports it as TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 256 bit keys, TLS 1.2)

Why isn't Fiddler able to make this connection?

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1 Answer 1

Reset to default
115

Seems that your client didn't try to connect via 1.2

Check: Tools > Fiddler Options > HTTPS It's set to <client>;ssl3;tls1.0

Add "tls1.2" to the protocols list

Edit: Refer to the image below for where to find the option: enter image description here

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7
  • 2
    I don't see those options in that place in fiddler.
    – Jonesome Reinstate Monica
    Commented May 24, 2017 at 1:22
  • 3
    In Fiddler 4 the option exists. look at this screenshot jackstromberg.com/2016/08/…
    – Neroon
    Commented May 24, 2017 at 5:05
  • it worked me, use this screen shot. jackstromberg.com/2016/08/…
    – Abhishek P
    Commented Aug 9, 2017 at 13:37
  • I suggested an edit. This error happens to me when I have ssl2 set in the same place.
    – Philip Rego
    Commented Aug 7, 2019 at 21:04
  • 2
    In Fiddler4 it's Tools > Options. And the option to add a Protocol only becomes visible if you check Decrypt HTTPS traffic, after which you can click No, go and add the Protocols needed and then uncheck the Decrypt HTTPS traffic option.
    – Aage
    Commented Nov 21, 2019 at 15:17

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