SendMail Function Throwing an NSRange Exception

I am trying to get the “sendmail” function to work, but it is giving me the following exception:

NSRangeException:
*** -[NSCFString substringToIndex:]: Range or index out of bounds

My Code looks like this:

sendmail (to: "bbolt@somecompany.com, bbolt@somecompany.com", subject: "Test Email", body: "Just a Test Email") 

any ideas?