ERR_SSL_PROTOCOL_ERROR for localhost from Visual Studio debug

Question

I am running a simple ASP.net web application. Chrome is showing the below error after running this.

localhost sent an invalid response.
Try running Windows Network Diagnostics.
ERR_SSL_PROTOCOL_ERROR

but my application is on http, not https.

but the URL is loading with https://localhost:54056/

config is also pointing to http only.

 <site name="tan-square" id="2">
            <application path="/" applicationPool="Clr4IntegratedAppPool">
                <virtualDirectory path="/" physicalPath="C:\Users\Myfolder\OneDrive\Downloads\tan-square" />
            </application>
            <bindings>
                <binding protocol="http" bindingInformation="*:54056:localhost" />
            </bindings>
        </site>

I don't understand where the problem is. Why is it loading with https?

What if you switch to another web browser? Chrome has been insane on pushing its own restrictions (on certificates and so on), so really not a good browser for debugging. — Lex Li
– Lex Li, Commented Mar 6, 2020 at 16:45

DeveloperDan · Accepted Answer · 2024-01-10 21:17:10Z

122

First, check your site web binding detail by the following detail:

Open visual studio, select your project.
right-click on the project and select properties.
under the Web tab and check your project url.

make sure there no such setting in your web.conifg file like below:

<system.webServer>
    <httpProtocol>
      <customHeaders>
        <add name="Strict-Transport-Security" 

        value="max-age=16070400; includeSubDomains" />
      </customHeaders>
    </httpProtocol>
</system.webServer>

When the browser sees this, it will remember, for the given number of seconds, that the current domain should only be contacted over HTTPS. In the future, if the user types http:// or omits the scheme, HTTPS is the default.

Clear your browser cache.

Another thing you could try to find the cause is open chrome and type chrome://net-internals/#hsts in the address bar (in edge type edge://net-internals/#hsts) and search for localhost:

The query shows “localhost” as being in the list of domains in the HSTS set.

The solution is deleting the domain from the cache. type “localhost” into the Delete domain text field, and hit Delete. After doing that when you query for “localhost” again you will receive a “Not found”.

edited Jan 10, 2024 at 21:17

DeveloperDan

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answered Mar 6, 2020 at 9:42

Jalpa Panchal

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10 Comments

Matheus Xavier Over a year ago

I did the chrome thing and it worked for me. Thanks!!

Eyal Over a year ago

For me, clearing chrome cache solved this issue.

OldBuildingAndLoan Over a year ago

Perfect! Nothing else worked for me.

Cardi DeMonaco Jr Over a year ago

Removing localhost from HSTS prison did the trick for me! Nothing else was working!!! Thanks!!!

Simon Over a year ago

I am running an .net 6 web project In VS2022 and there is no section 'Web' in the project settings.

|

Jamal Qudah · Accepted Answer · 2021-03-14 08:59:53Z

5

Just create new Virtual Directory:

1-right-click on the project and select properties.

2-under the Web tab change your project url by changing the localhost to http://localhost:48333/ .

3- click Create Virtual Directory.

4- make sure you don't have this in web.config

<system.webServer>
    <httpProtocol>
      <customHeaders>
        <add name="Strict-Transport-Security" value="max-age=16070400; includeSubDomains"/>
      </customHeaders>
    </httpProtocol>
</system.webServer>

answered Mar 14, 2021 at 8:59

Jamal Qudah

811 silver badge3 bronze badges

1 Comment

PhillipPDX Over a year ago

This is by far the most simple solution. Just remember to be sure that your Web.confg transform is proper as show in the example above by Jalapa_Panchal.

Muzaffer Galata · Accepted Answer · 2022-12-08 17:24:58Z

2

In my case "clearing SSL State" has solved my issue.

Open the Start menu.
Search for and open Internet Options.
In the dialog box that appears, select the Content tab.
Click Clear SSL State.

answered Dec 8, 2022 at 17:24

Muzaffer Galata

6421 gold badge12 silver badges25 bronze badges

Comments

VineetYadav · Accepted Answer · 2021-03-30 21:05:26Z

1

If you are running .net core, just run Visual Studio as admin, or go to bin\Debug\netcoreapp3.1 directory, and issue. Wierdly, .net core. .net core surprisingly dont give any error.

%USERPROFILE%\\.dotnet\\tools\\dotnet-lambda-test-tool-3.1.exe --port 5059

change port number to whatever.

answered Mar 30, 2021 at 21:05

VineetYadav

7831 gold badge5 silver badges10 bronze badges

1 Comment

Tom John Over a year ago

Interestingly running VS as admin solved the problem for me, then subsequently running VS without elevated privileges the browser no longer reported the error.

Arun Raut · Accepted Answer · 2022-10-06 07:13:04Z

1

Go to launch settings change the launch URL to https instead of http, it will ask you to add self generated ssl , click Yes and it Run the project. Hope this will help you

answered Oct 6, 2022 at 7:13

Arun Raut

392 bronze badges

Comments

Mohammad · Accepted Answer · 2023-03-10 16:19:26Z

0

VS will do this automatically if you add an ssl port to the iisbindings section of launchsettings.json. There is no UI to do it but you can edit the file directly.

{
    "iisSettings": {
    "windowsAuthentication": false,
    "anonymousAuthentication": true,
    "iis": {
        "applicationUrl": "https://localhost/WebApplication",
        "sslPort": 443
    },
    "iisExpress": {
        "applicationUrl": "https://localhost:62686",
        "sslPort": 44391
    }
},

answered Mar 10, 2023 at 16:19

Mohammad

9718 silver badges15 bronze badges

Comments

ronenfe · Accepted Answer · 2024-05-18 09:59:11Z

0

Just use IIS, waste of time to solve Microsoft bugs.

answered May 18, 2024 at 9:59

ronenfe

2,4741 gold badge25 silver badges36 bronze badges

Comments

SendETHToThisAddress · Accepted Answer · 2025-03-20 17:35:20Z

0

I also was getting the same error message, but yet another root cause for me. In my case it was a null reference error due to a property I never set in the ViewBag. I had a condition like this in my .cshtml file:

@if (ViewBag.Property1)
{
    // do stuff
}

But the property was never set. You'd think this would throw a null reference error or just evaluate to false, but no.

ViewBag.Property1 = "some value";

After setting the ViewBag property in my controller the error went away.

answered Mar 20 at 17:35

SendETHToThisAddress

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Comments

Mounika · Accepted Answer · 2022-03-11 07:17:26Z

-5

Change default browser to Chrome and the issue is solved.

answered Mar 11, 2022 at 7:17

Mounika

3

1 Comment

Community Over a year ago

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