Hope that this will solve your problem.
Dim toAddressList As String = "tomail1@gmail.com,tomail2@gmail.com,tomail3@gmail.com,tomailn@gmail.com"
Dim toCClist As String = "tomail1@gmail.com,tomail2@gmail.com,tomail3@gmail.com,tomailn@gmail.com"
Dim toBCClist As String = "tomail1@gmail.com,tomail2@gmail.com,tomail3@gmail.com,tomailn@gmail.com"
myMail.AddMultipleCC(toCClist)
myMail.AddMultipleBcc(toBCClist)
myMail.AddMultipleTo(toAddressList)
Now execute the query this will work fine. thanks for spending your time to read this.