unable to open .MSG file after creation

Hello,

I have installed Chilkat api using nuget package manager in visual studio and, I have created .msg file using the below code:

Chilkat.Email email = new Chilkat.Email();
            //email.LoadEml(@"E:\MailTest\Untitled.msg");
            email.Subject = "This is a test";
            email.Body = "Hello Message .... mail... Mail.. MAil....";
            email.From = "support@chilkatsoft.com";
            email.AddTo("Matt", "matt@chilkatsoft.com");
            email.SaveEml(@"E:\MailTest\Testmail.msg");

.MSG file is being created at the specified location but, it throwing the below error when I am trying to open the file :

ERROR: We can't open 'file_location.msg'. It's possible the file is already open, or you don't have permission to open it.

I am opening the file from super admin account only and all permissions are allowed.