error after publishing app: The specified string is not in the form required for an e-mail address. - asp.net

Question

I am trying to create a program to send an email. my program works fine when I run it on local, but display an error after I publish it to the server.
this program trying to send an email inside gridview.
here is the gridview :
checkbox || email1 || email2
checkbox || bla2.smptserver.com || bla3.smptserver.com
checkbox || || bla3.smptserver.com
if email if email in column email1 is not null then the email will be send directly.
if email in column email1 is null then the email will be send to the recipient in column email2.
here is my code so far :
Private Sub sendEmail()
Dim Username2 As String = System.Configuration.ConfigurationManager.AppSettings("username")
Dim Password2 As String = System.Configuration.ConfigurationManager.AppSettings("1234")
Dim Server2 As String = System.Configuration.ConfigurationManager.AppSettings("namesmtp.server.com")
Dim X As Integer
For X = 0 To GridView1.Rows.Count - 1
Dim chkBox As CheckBox = CType(GridView1.Rows(X).Cells(18).Controls(1), CheckBox)
If chkBox.Checked = True Then
Dim email2 As String = ""
Dim no As Integer = CInt(GridView1.Rows(X).Cells(0).Text)
Dim id As String = Trim(GridView1.Rows(X).Cells(1).Text)
Dim name As String = Trim(GridView1.Rows(X).Cells(2).Text)
Dim item As String = Trim(GridView1.Rows(X).Cells(3).Text)
Dim size As String = Trim(GridView1.Rows(X).Cells(4).Text)
Dim qty As String = Trim(GridView1.Rows(X).Cells(5).Text)
Dim clr As String = Trim(GridView1.Rows(X).Cells(6).Text)
Dim type As String = Trim(GridView1.Rows(X).Cells(7).Text)
Dim area As String = Trim(GridView1.Rows(X).Cells(8).Text)
Dim ab As String = Trim(GridView1.Rows(X).Cells(9).Text)
Dim reason As String = Trim(GridView1.Rows(X).Cells(10).Text)
For Each row As GridViewRow In GridView1.Rows
If row.RowType = DataControlRowType.DataRow Then
Dim chkRow As CheckBox = TryCast(row.Cells(18).FindControl("chkCtrl"), CheckBox)
If chkRow.Checked Then
Dim spv As String = Trim(row.Cells(16).Text)
Dim mgr As String = Trim(row.Cells(17).Text)
sql = "update tbl_name set [Attire App] = 'Approved', [Attire Date] = #ADate, [SPV App] = (case when [SPV id] = '' then 'Approved' else [SPV App] end) where No = '" & Convert.ToUInt32(no) & "' and [Badge ID]= '" + Convert.ToString(id) + "' and Uniform = '" + item + "' and [Attire App] is null"
Dim sqlcomm As New SqlCommand(sql, con)
sqlcomm.Parameters.AddWithValue("#ADate", Now.Date)
sqlcomm.ExecuteNonQuery()
End If
End If
Next
If email2 <> "" Then
email2 = Trim(GridView1.Rows(X).Cells(16).Text)
Else
email2 = Trim(GridView1.Rows(X).Cells(17).Text)
End If
Try
Dim EmailMessage As System.Net.Mail.MailMessage = New System.Net.Mail.MailMessage
EmailMessage.From = New MailAddress("mail.address#something.com")
EmailMessage.To.Add(email2)
EmailMessage.Subject = "Attire Request"
EmailMessage.IsBodyHtml = True
Dim link As String = "Some link"
EmailMessage.Body = "There is a request for attire from employee. Please approve the request by using the following link Click here "
Dim smtp As New SmtpClient(Server2)
Dim basicAuthenticationInfo As New System.Net.NetworkCredential(Username2, Password2)
smtp.Credentials = basicAuthenticationInfo
smtp.Send(EmailMessage)
Catch ex As Exception
lblError.Text = ex.Message
lblError.Visible = True
End Try
End If
Next
End Sub
column email1 reside on gridview cell 16.
column email2 reside on gridview cell 17.
it's work fine but after I publish it, it's throws an errror.
the error display is 'The specified string is not in the form required for an e-mail address. '
Thanks in advance...