Страница может иметь только одну ошибку тега формы на стороне сервера

<%@ Page Language="C#" MasterPageFile="~/Manager.master" AutoEventWireup="true" CodeFile="MangerComposemessge.aspx.cs" Inherits="MangerComposemessge" Title="Untitled Page" %>


<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">

    <style type="text/css">
        .style1
        {
            width: 100%;
            border: 6px solid #FFFFCC;
            background-color: #FFFFCC;
        }
        .style2
        {
            width: 228px;
        }
    </style>

</asp:Content>
<asp:Content ID="Content2" runat="Server" ContentPlaceHolderID="ContentPlaceHolder1" >
<form id="frm" runat="server">

    <p>
        &
    </p>
    <p>
        &
        <table class="style1">
            <tr>
                <td class="style2">
        
        <asp:Label ID="Label4" runat="server" Text="TO"></asp:Label>
                </td>
                <td>

        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

        <asp:TextBox ID="TextBox1" runat="server" Width="222px"></asp:TextBox>
                </td>
            </tr>
            <tr>
                <td class="style2">
        
        <asp:Label ID="Label5" runat="server" Text="Subject"></asp:Label>
                </td>
                <td>

 <asp:TextBox ID="TextBox2" runat="server" Width="223px"></asp:TextBox>
                </td>
            </tr>
            <tr>
                <td class="style2">
        
        <asp:Label ID="Label6" runat="server" Text="Message"></asp:Label>
                </td>
                <td>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
        <asp:TextBox ID="TextBox3" runat="server" Height="97px" TextMode="MultiLine"

            Width="315px"></asp:TextBox>
                </td>
            </tr>
            <tr>
                <td class="style2">
                    
                    <asp:Label ID="Label7" runat="server" Text="Attachment"></asp:Label>
                </td>
                <td>
       &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
       <asp:TextBox ID="TextBox4" runat="server"></asp:TextBox>
        <asp:Button ID="Button2" runat="server" Text="Browse" />
                </td>
            </tr>
            <tr>
                <td class="style2">
                    &nbsp;</td>
                <td>
                    &nbsp;</td>
            </tr>
            <tr>
                <td class="style2">
                    &nbsp;</td>
                <td>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
        <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Send" />
                </td>
            </tr>
        </table>
        <br />
    </p>

    </form>
</asp:Content>