Powerbi report server custom authentication

Hi v-qiuyu-msft,

I have Power BI Report Server and I have followed all steps as mentioned in this article. Now when I browse, login page shows correctly. However whenever I click eiher "Register User" button OR "Login" button, I get following exception

An error occurred while attempting to add the account. Request for the permission of type 'System.Data.SqlClient.SqlClientPermission, System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

In article's Step 3 it is mentioned to add <CodeGroup> in RSSrvPolicy.config file. However the step description is very confusing for me

Add the following <CodeGroup> element after the existing code group in the security policy file that has a URL membership of $CodeGen as indicated below and then add an entry as follows to RSSrvPolicy.config. Make sure to change the below path according to your ReportServer installation directory:

<CodeGroup
	class="UnionCodeGroup"
	version="1"
	Name="SecurityExtensionCodeGroup" 
	Description="Code group for the sample security extension"
	PermissionSetName="FullTrust">
<IMembershipCondition 
	class="UrlMembershipCondition"
	version="1"
	Url="C:\Program Files\Microsoft Power BI Report Server\PBIRS\ReportServer\bin\Microsoft.Samples.ReportingServices.CustomSecurity.dll"/>
</CodeGroup>

I already have one CodeGroup which has Member Url="$CodeGen$/*". So With above description, I am not getting that either I have to replace this URL in this CodeGroup with the path of dll (as mentioned in article) OR just have to add new CodeGroup (as given in article) below of existing code group which contains Member Url = "$CodeGen$/*".

When I added new CodeGroup below of $CodeGen Member CodeGroup as shown in picture then I get same permission error

Can you please guide me how to resolve this Permission issue?

Thanks.