Several Users have claimed that they are facing ERR_SPDY_INADEQUATE_TRANSPORT_SECURITY error and this error is affecting the web developers and it interferes with the development process. And it is also called NS_ERROR_NET_INADEQUATE_SECURITY error and it generally happens while accessing websites hosted on IIS 10.0. If you are also struggling hard to get past the error then you totally rely on this blog as we will try our best to provide all the feasible solution to get past the error. So without any further delay let’s get started with the discussion.

What Causes ERR_SPDY_INADEQUATE_transport_Security?

You are likely to face the above mention error because of using an outdated version of Chrome, old and corrupted browser cookies, or HTTP/2 is enabled. Furthermore, if your Windows Server is using some weaker ciphers & protocols then you are likely to face the above mention error.


Method 1: Update the Chrome Browser

As we told earlier you are likely to face the above mention error due to outdated chrome browser, so we suggest you to update the Chrome browser:

Here’s how:

  • Tap on the three vertical dots from the upper right corner in Chrome and select Settings>then click on the About Chrome Setting from the left pane will trigger the search for Chrome Updates
  • Once the update is installed, click on the Relaunch button

Method 2: Use IIS Crypto 2

In the method we suggest you to use IIS Crypto 2 as several users have claimed success over this error after applying this method;

So follow the below mention guidelines to proceed:

  • First of all download IIS Crypto 2>then install and launch the program
  • Tap on the Best Practices option at the bottom of the window>after that the best practice for your PC will be checked by Crypto 2
  • Finally click on Apply to save these configurations
Method 3: Disable SPDY or HTTP/2 Protocol

In this method we suggest you to disable the HTTP/2 Protocol in Chrome. And to do the same follow the below mention guidelines:

  • Right-Click on the Chrome icon on your desktop screen and select Properties>then Switch to the Shortcut tab on the Properties window
  • Under the Target box, add one of the scripts below to the end of the written text:



  • Finally click on OK to save the changes
Method 4: Modify Windows Registry

If none of the above mentioned methods works for you then edit the Windows Registry and try loading the web page you were unable to access.

Here’s how:

  • On your keyboard press Windows + R keys together to open Run Command Box>then type in regedit and press Enter key
  • Go to the below mention path:


  • After that right-click he right section of the registry and press New from the resulting drop down menu>select DWORD (32-bit) Value
  • Then type in EnableHttp2Tls as the folder name and set the DWORD value as 0>Create another new DWORD with EnableHttp2Cleartext and then set the DWORD value to 0 too.
  • Once done then finally Restart your computer.
Method 5: Use another Browser

If none of the above mentioned methods works for you then it is suggested to switch to a different browser. You can go for other reliable browsers like Microsoft Edge.

Bottom Line

We really hope that you liked the blog and it was helpful for you in resolving ERR_SPDY_INADEQUATE_TRANSPORT_SECURITY error. Thanks for Reading.