Exception while trying to connect a server w/o a certificate

Hi,

When I debug my app, I get exception on the line of code:
System.Net.ServicePointManager.ServerCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true;

The exception is:
" Object of type 'System.Func`5[System.Object,System.Security.Cryptography.X509Certificates.X509Certificate,System.Security.Cryptography.X509Certificates.X509Chain,System.Net.Security.SslPolicyErrors,System.Boolean]' cannot be converted to type 'System.Net.Security.RemoteCertificateValidationCallback'. (ArgumentException)] "

Can't fix it in anyway I tried,
please help