Access denied when accessing powershell in webapplication

Question

1. Below is my powershell script:

   #Accept input parameters  
   Param(  
       [Parameter(Position=0, Mandatory=$false, ValueFromPipeline=$true)]  
       [string] $Office365Username,  
       [Parameter(Position=1, Mandatory=$false, ValueFromPipeline=$true)]  
       [string] $Office365Password,
       [string]$GroupName
   )
   
   #Remove all existing Powershell sessions  
   Get-PSSession | Remove-PSSession   
   
   #Did they provide creds?  If not, ask them for it.
   if (([string]::IsNullOrEmpty($Office365Username) -eq $false) -and ([string]::IsNullOrEmpty($Office365Password) -eq $false))
   {
   
       $SecureOffice365Password = ConvertTo-SecureString -AsPlainText $Office365Password -Force      
   
       #Build credentials object  
       $Office365Credentials  = New-Object System.Management.Automation.PSCredential $Office365Username, $SecureOffice365Password  
   }
   else
   {   
       #Build credentials object  
       $Office365Credentials  = Get-Credential
   }
   
   #Create remote Powershell session  
   $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $Office365Credentials -Authentication Basic -AllowRedirection
   
   #Import the session  
   Import-PSSession $Session
   #cmds
   
   $result=Get-DistributionGroup -ResultSize Unlimited  
   return  $result
   #Clean up session  
   Remove-PSSession $Session
   

2. Below is my C# code

    public string GetAllGroups()
        {
            int count = 1;
            string getDListScript = @"C:\inetpub\wwwroot\O365Service\Scripts\GetDList.ps1";
   
            string userName = "j*****";
            string password = "****";
            try
            {
                using (var ps = PowerShell.Create())
                {
                    Runspace runSpace = RunspaceFactory.CreateRunspace();
                    runSpace.Open();
                    ps.Runspace = runSpace;
   
                    ps.AddCommand(getDListScript).AddParameter("Office365Username", userName).AddParameter("Office365Password", password);
                    //IAsyncResult async = ps.BeginInvoke();
                    //StringBuilder stringBuilder = new StringBuilder();
   
                 var   results = ps.Invoke();
                 PSDataCollection<ErrorRecord> errors = ps.Streams.Error;
                 if (errors != null && errors.Count > 0)
                 {
                     StringBuilder sb = new StringBuilder();
                     foreach (ErrorRecord err in errors)
                     {
                         sb.Append(err.ToString());
                     }
                     System.IO.File.WriteAllText(@"C:\inetpub\wwwroot\RestService\bin\err.text", sb.ToString());
                 }
   
                 count = results.Count;
   
   
                }
            }
            catch (Exception ex)
            {
                return ex.Message.ToString();
            }
            return count.ToString();
   

   }

When i am executing the C# code on server from Console application it is working fine but when i am executing it from Webservice it is giving me the below exception

[outlook.office365.com] Connecting to remote server outlook.office365.com failed with the following error message : Access is denied. For more information, see the about_Remote_Troubleshooting Help topic.Cannot validate argument on parameter 'Session'. The argument is null. Provide a valid value for the argument, and then try running the command again.The term 'Get-DistributionGroup' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.

I have set execution policy to unrestricted of the server.