Visual Studio Web Application Debugging using SSL with Chrome Error

If you are trying to debug your website using Visual Studio 2017 and Chrome with an HTTPS link you might encounter an error in Chrome because of the new security restrictions.

I was asked by someone for help to fix an error message being displayed in Chrome ERR_SPDY_INADEQUATE_TRANSPORT_SECURITY on their Windows 10 (1607) desktop.

If you’ve not tried this before you simply view the properties of your Web Application and set SSL Enabled to True.


Web Application | Properties | SSL Enabled

Now we have to make sure the SSL URL from the previous step is configured as the Project URL. In Solution Explorer right click your Web Application and select Properties | Web


Web Application | Properties | Web

If we start a debugging session, we will immediately be prompted  to trust the certificate (if this is the first run).  Press the Yes button to proceed.


Would you like to trust the IIS Express SSL certificate?

You will now be prompted to install the generated root certificate so the browser (Chrome/Edge/IE) will trust it.  Click Yes to proceed.


Security Warning | Do you want to install this certificate?

If you see any errors in Chrome using this certificate you will have to disable some protocols (IISCrypto) and some ciphers – Launch the IIS Crypto application, Click the Best Practices button and then click Apply (you will have to reboot your PC to get these changes to take effect).


IIS Crypto 2.0

If everything has suceeded, after the reboot launch Visual Studio again, open your Web Application and start debugging!  You should see the following (not including the About Chrome):


Debug your application with IIS Express w/SSL using Google Chrome

I was not able to reproduce this error on my Windows 10 Insiders Build so I suspect this maybe specific to 1607 or earlier builds.


About Wes MacDonald

Wes MacDonald is a DevOps Consultant for LIKE 10 INC., a DevOps consulting firm providing premium support, guidance and services for Azure, Microsoft 365 and Azure DevOps.

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