Issue  
1.  Visual Studio User account login failed when try to login.

Solution  


1. Right click on the visual studio > go to properties > shortcut tabs > click on Open File Location button and find "devenv.exe.config" open

 2.  Open devenv.config.exe and modify accordingly as below 



3.   Add the below details under system.net section in devenv.exe.config file 

 <system.net>
<defaultProxy useDefaultCredentials="true" enabled="true">
<proxy usesystemdefault="true"/>
</defaultProxy> 
      <settings>
        <ipv6 enabled="true"/>
<ServicePointManager except100Continue="false"/>
      </settings>

    </system.net>


4.  Finally, Close Visual Studio and Open, Login with User account, No error.