Rewrite the code added in sendmail function to get the credential, It will save time to get email credential from database everytime.
string s43 = "select top 1 mailid,password from EmailTable order by id desc";
DataTable d47 = cn.viewdatatable(s43);
companymailid = d47.Rows[0]["mailid"].ToString();
password = d47.Rows[0]["password"].ToString();
for (int m = 0; m < d7.Rows.Count; m++)
{
email = d7.Rows[m]["email"].ToString();
sendmail(companymailid,password,email );
}