HttpException occurred(login panel)

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C#

ASP.NET

WebForms

Hello ı used web user control but ı get this mesage
HttpException occurred
Control 'LoginPanel_txtPassword' of type 'TextBox' must be placed inside a form tag with runat=server.

this is my codes:

<%if (user == null) { %>
    
    Şifre : <br />
    <asp:TextBox ID="txtPassword" runat="server"></asp:TextBox><br />
    <asp:Button ID="btnLogin" runat="server" Text="Button" OnClick="btnLogin_Click" /><br />
Kullanıcı Adı : <br />
   <asp:TextBox ID="txtUserName" runat="server"></asp:TextBox><br />
    
<%} else { %>
    Merhaba, <%= user.UserName %><br />
    <asp:LinkButton ID="lbLogOut" runat="server" OnClick="lbLogOut_Click">lbLog Out</asp:LinkButton>
<%}%>

and my code behind

protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected Users user 
        {
            get {return Session["user"]as Users; }
            set { Session["user"] = value; }
        }
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void btnLogin_Click(object sender, EventArgs e)
        {
            UserResposite _userResposite = new UserResposite();
            user = _userResposite.CheckUser(txtUserName.Text, txtPassword.Text);
            Response.Redirect(Request.Url.PathAndQuery);
        }

        protected void lbLogOut_Click(object sender, EventArgs e)
        {
            Session.Abandon();
            Response.Redirect(Request.Url.PathAndQuery);
        }
    }

ı need help