Sending Email error with To/From address session values

mailMessage.From = New System.Net.Mail.MailAddress(Session("MembEmail").ToString()) mailMessage.[To].Add(New MailAddress(Session("Sh0")).ToString()) If I replace the above sessions with typed email addresses - the emails work.  I can't figure out what is wrong with the sessions...I beleive it might be the syntax.  Can someone "see" syntax error with the session value syntax?