getting error "The underlying connection was closed "

Question

I am getting this error “The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.” on mvc application.

 

Below web config code:

 

<system.web>

<compilation debug="false" targetFramework="4.6"/>

<httpRuntime targetFramework="4.6" requestValidationMode="2.0" enableVersionHeader="false"/>

<machineKey validationKey="FF4636C4DF933BE453F9B94810661C5F5625794E5DCA46A3C281EB18CC5410386A4B38F5E4C7D7106C049C9EB10F31C2F4E76E74616ABD36DC6C64AF2BFF6801" decryptionKey="667F9049734567FF3E7BC7031DF4B4431F992A447CE2FB3258F6EE989BA82E8F" validation="SHA1" decryption="AES"/>

<httpHandlers>

<add path="*" verb="OPTIONS" type="System.Web.DefaultHttpHandler" validate="true"/>

<add path="*" verb="TRACE" type="System.Web.DefaultHttpHandler" validate="true"/>

<add path="*" verb="HEAD" type="System.Web.DefaultHttpHandler" validate="true"/>

</httpHandlers>

<authorization>

<deny verbs="OPTIONS" users="*"/>

<deny verbs="TRACE" users="*"/>

<deny verbs="HEAD" users="*"/>

</authorization>

<authentication mode="Forms">

<forms loginUrl="~/Login/Login" defaultUrl="~/Home/Home" name="testdb" cookieless="UseCookies" requireSSL="true" slidingExpiration="false" protection="All"/>

</authentication>

<httpCookies httpOnlyCookies="true" requireSSL="true"/>

<sessionState timeout="20"/>

<customErrors mode="On" defaultRedirect="~/Home/ErrorPage"/>

</system.web>

<system.webServer>

<httpProtocol>

<customHeaders>

<add name="X-Frame-Options" value="DENY"/>

</customHeaders>

</httpProtocol>

<validation validateIntegratedModeConfiguration="false"/>

</system.webServer>

 

 

When i published code.I got this message "The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel." on error log.But when i set requireSSL="false" in web config it's working Properly.but in security tool it shows vulnerabiltiy.

Please help!