Hey guys, i need a help.

fiddler.network.https> HTTPS handshake to api.imvu.com (for #20) failed. System.Security.Cryptography.CryptographicException Errore non specificato.

 this problem is present with any asite/application 

i use win10, fiddler version v5.0.20181.14337 

Best reguards

complete log

17:19:06:9936 Assembly 'C:\Users\Mirko\AppData\Local\Programs\Fiddler\CertMaker.dll' was not found. Using default Certificate Generator.
17:19:07:0096 /Fiddler.CertMaker> Using .‰+˜ for certificate generation; UseWildcards=True.
17:19:07:0096 /Fiddler.CertMaker> Root Certificate located; private key in container 'd57011b752b860db21f505c287c6216a_cf348a6d-1761-4707-bd62-1aace5e3197f'
17:19:07:0252 /Fiddler.CertMaker> Invoking CertEnroll for Subject: CN=*.imvu.com, O=DO_NOT_TRUST, OU=Created by http://www.fiddler2.com; Thread's ApartmentState: MTA
17:19:08:1282 /Fiddler.CertMaker> Finished CertEnroll for 'CN=*.imvu.com, O=DO_NOT_TRUST, OU=Created by http://www.fiddler2.com'. Returning cert
17:19:08:1282 fiddler.network.https> HTTPS handshake to api.imvu.com (for #2) failed. System.Security.Cryptography.CryptographicException Unspecified Error.

Hello,

Could you, please, try to reset your Fiddler root CA certificate. You can do this from Tools\Options... menu. Then go to the HTTPS tab. There is an "Actions" button. When you click it, a drop-down menu appears. Please, click "Reset All Certificates."

Regards,
Simeon
Progress Telerik

Thanks for the reply,
I tried to follow your directions but the problem was not solved
I also tried to uninstall and reinstall fiddler but it did not work

Hello Stefano,

It could be that there are some old Fiddler certificates in your certificate store, which for some reason are not cleared during the reset, so lets try a manual approach.

Firstly, make sure that the 'Decrypt HTTPS traffic' checkbox in Fiddler's HTTPS Options is NOT checked and close Fiddler.

Then in the Windows' taskbar search box type 'Manage user certificates' and press enter. The Certificate manager for the current user will open.
Locate all certificates Issued By: DO_NOT_TRUST_FiddlerRoot and delete them. Please, be careful to not delete any other certificates.

If you have administrative rights, type 'Manage computer certificates' into the Windows' taskbar search box. The Certificate manager for the local computer will open.
Locate all certificates Issued By: DO_NOT_TRUST_FiddlerRoot and delete them. Please, be careful to not delete any other certificates.

Open Fiddler and check the 'Decrypt HTTPS traffic' checkbox. Some prompts, asking to trust the newly generated CA certificate, should appear. Trust the certificate and restart Fiddler.

I hope that this would solve your problem.

Regards,
Simeon
Progress Telerik

I followed the instructions without encountering errors, after removing all the certificates I reopened fiddler, rehabilitated "https decypt", given trust to the certificates and restarted the program.
but, the first lines of the log are these

23:49:51:3490 Fiddler Running...
23:49:51:3490 AutoProxy failed. Disabling for this network.
23:49:51:3490 fiddler.network.https> HTTPS handshake to www.fiddler2.com (for #1) failed. System.Security.Cryptography.CryptographicException Unspecified Error

always the same problem..

I do not know if it can help, it appeared later, sorry for double post

:3960 Windows 8+ AppContainer isolation feature detected.
23:50:15:7328 Assembly 'C:\Users\Mirko\AppData\Local\Programs\Fiddler\CertMaker.dll' was not found. Using default Certificate Generator.
23:50:15:7428 /Fiddler.CertMaker> Using .‰+˜ for certificate generation; UseWildcards=True.
23:50:15:7538 /Fiddler.CertMaker> Root Certificate located; private key in container '25fd8d256611f702ea5d7085e2422a29_cf348a6d-1761-4707-bd62-1aace5e3197f'
23:50:15:7568 /Fiddler.CertMaker> Invoking CertEnroll for Subject: CN=*.vortex-win.data.microsoft.com, O=DO_NOT_TRUST, OU=Created by http://www.fiddler2.com; Thread's ApartmentState: MTA
23:50:16:8359 /Fiddler.CertMaker> Finished CertEnroll for 'CN=*.vortex-win.data.microsoft.com, O=DO_NOT_TRUST, OU=Created by http://www.fiddler2.com'. Returning cert
23:50:16:8369 fiddler.network.https> HTTPS handshake to v10.vortex-win.data.microsoft.com (for #3) failed. System.Security.Cryptography.CryptographicException Unspecified Error

Hello,

23:49:51:3490 AutoProxy failed. Disabling for this network.
Assuming that the Gateway Options of Fiddler are set to use the system proxy, I suppose that your system proxy settings are set to automatically detect the proxy (using the WPAD prtocol) or to use an automatic configuration script (PAC script). Fiddler handles these two options in a similar manner.

However, Fiddler's behavior is to disregard the AutoProxy if the first request fails. I am not quite sure if this behavior is desirable because a request could fail for many reasons. Slow connection, bad connectivity, timeouts, busy server etc. After Fiddler disregards the AutoProxy, for the following requests it tries to send them to the system's default gateway. And if your network is configured to do not allow direct Internet access, when Fiddler tries to make a SSL handshake with the server it receives an unexpected result which causes the CryptographicException. Please, be aware that this are only assumptions which I make because I cannot reproduce the problem locally.

Fortunately, there is a Fiddler preference which changes the described behavior. In the Fiddler's QuickExec command line (Alt + Q), please , type the following command: "prefs set fiddler.network.gateway.UseFailedAutoProxy True" (without the quotes) and restart Fiddler. You could check that the preference is set by typing about:config into the QuickExec. The about:config tab will open showing the current Fiddler preferences.

The 'fiddler.network.gateway.UseFailedAutoProxy' pref will force Fiddler to stick with the AutoProxy.

Please, let me know if my assumptions are correct and if setting the pref helped.

Regards,
Simeon
Progress Telerik

Thanks for reply.

I set the preference as you recommend and everything is successful.

after the restart the situation is as follows

14:34:16:4768 Fiddler Running...

14:34:16:4778 fiddler.network.https> HTTPS handshake to www.fiddler2.com (for #1) failed. System.Security.Cryptography.CryptographicException Unpecified Error.

14:34:16:5197 Windows 8+ AppContainer isolation feature detected.
14:34:21:6985 Assembly 'C:\Users\Mirko\AppData\Local\Programs\Fiddler\CertMaker.dll' was not found. Using default Certificate Generator.
14:34:21:7085 /Fiddler.CertMaker> Using .‰+˜ for certificate generation; UseWildcards=True.
14:34:21:7255 fiddler.network.https> HTTPS handshake to v10.vortex-win.data.microsoft.com (for #2) failed. System.Security.Cryptography.CryptographicException Unspecified Error.