Api returns error below:
“Object reference not set to an instance of an object.”

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

Line 18:
Line 19:
Line 20: string emailid = Request.QueryString[“email”].ToString();
Line 21:
Line 22: if (emailIsValid(emailid) == true)

Source File: c:\inetpub\vhosts\codzz.com\httpdocs\mashape\chkgmail.aspx.cs Line: 20

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.]
mashape_chkgmail.Page_Load(Object sender, EventArgs e) in c:\inetpub\vhosts\codzz.com\httpdocs\mashape\chkgmail.aspx.cs:20
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +51
System.Web.UI.Control.OnLoad(EventArgs e) +92
System.Web.UI.Control.LoadRecursive() +54
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +772

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.17929