CREATE statement fails in ASP.NET MVC - html

Question

My create statement could not work suddenly and it goes straight to an error message (Account cannot be created). I am not sure where I went wrong as I did not make any modification to it at all. In total, I have encountered this problem THRICE and my only solution is to make a new project for it to work again with the same exact codes. Any suggestions to ensure no such thing happen again in the future? Thank you in advance! Here are my codes in the controller:
[HttpPost]
public IActionResult CreateUser(Users usr)
{
if (!ModelState.IsValid)
{
ViewData["Message"] = "Invalid Input";
ViewData["MsgType"] = "warning";
return View("CreateUser");
}
else
{
string insert = #"INSERT INTO WBUsers(UserId, UserPw,FullName, Email, UserRole, Dob, ContactNo, usr.Billing_Address)
VALUES('{0}', HASHBYTES('SHA1', '{1}'), '{2}', '{3}', '{4}', '{5}', {6}, '{7}')";
if (DBUtl.ExecSQL(insert, usr.UserId, usr.UserPw, usr.FullName, usr.Email, usr.UserRole, usr.Dob, usr.ContactNo, usr.Billing_Address) == 1)
{
string template = #"Hi {0},<br/><br/>
Welcome to WorldBay!
Your userid is <b>{1}</b> and password is <b>{2}</b>. Please change your password upon login.
<br/><br/>Adminstrator";
string title = "Account Sign Up";
string message = String.Format(template, usr.FullName, usr.UserId, usr.UserPw);
string result = "";
bool outcome = false;
outcome = EmailUtl.SendEmail(usr.Email, title, message, out result);
if (outcome)
{
ViewData["Message"] = "Account has been created";
ViewData["MsgType"] = "success";
}
else
{
ViewData["Message"] = result;
ViewData["MsgType"] = "warning";
}
}
else
{
ViewData["Message"] = "Account cannot be created";
ViewData["MsgType"] = "danger";
}
return View("CreateUser");
}
}
DBUtil code consists of:
public static int ExecSQL(string sql, params object[] list)
{
List<String> escParams = new List<String>();
foreach (object o in list)
{
if (o == null)
escParams.Add("");
else
escParams.Add(EscQuote(o.ToString()));
}
DB_SQL = String.Format(sql, escParams.ToArray());
int rowsAffected = 0;
using (SqlConnection dbConn = new SqlConnection(DB_CONNECTION))
using (SqlCommand dbCmd = dbConn.CreateCommand())
{
try
{
dbConn.Open();
dbCmd.CommandText = DB_SQL;
rowsAffected = dbCmd.ExecuteNonQuery();
}
catch (System.Exception ex)
{
DB_Message = ex.Message;
rowsAffected = -1;
}
}
return rowsAffected;
}