My Asp.net page doesn't want to load - html

Question

I'm working on a project and whenever I try to load this page it gives me the same error everytime. Project is being worked on in Visual Studio 2015. What the goal is that users can fill in their name, email and a message they want to send to the owner of the site. Whenever the user is done with the message they click on the button, the button with the text verzenden, and a message is shown below if it is sent correctly or not. The problem is not the code however, I can manage that on myself.
Html code , this is all wrapped in a contentplaceholder because I have made a masterpage for the project :
<form id="Form1" runat="server">
<table>
<tr>
<td>
<br />
<br />
<h1> Stuur ons een berichtje</h1>
<br />
<br />
<p>Alle berichtjes worden ook verstuurd naar info#waasseschrijnwerken.be. Als het correct is verstuurd ontvangt u een bevestigingsmail.</p>
<br />
<br />
<asp:Label ID="lblnaam" runat="server" Text="Naam: "></asp:Label>
<asp:TextBox ID="txtnaam" runat="server"></asp:TextBox>
<asp:Label ID="lblmail" runat="server" Text="Emailadres: "></asp:Label>
<asp:TextBox ID="txtmail" runat="server"></asp:TextBox>
<br />
<br />
<asp:Label ID="lblbericht" runat="server" Text="Bericht: "></asp:Label>
<br />
<br />
<asp:TextBox ID="txtbericht" runat="server" Height="200px" Width="750px"></asp:TextBox>
<br />
<br />
<br />
<asp:Button ID="btnVerzend" runat="server" Text="Verzenden" />
<br />
<br />
<br />
<asp:Label ID="lblres" runat="server" Text="Label" Visible="False"></asp:Label>
<br />
<br />
<br />
</td>
</tr>
</table>
</form>
Translation: One page can only have one form-label with runat server

Answer 1

Check the masterpage for a <form> tag with runat="server". ASP.NET only allows one of these per page.
You can just remove it from your code above;
<table>
<tr>
<td>
<br />
<br />
<h1> Stuur ons een berichtje</h1>
<br />
<br />
<p>Alle berichtjes worden ook verstuurd naar info#waasseschrijnwerken.be. Als het correct is verstuurd ontvangt u een bevestigingsmail.</p>
<br />
<br />
<asp:Label ID="lblnaam" runat="server" Text="Naam: "></asp:Label>
<asp:TextBox ID="txtnaam" runat="server"></asp:TextBox>
<asp:Label ID="lblmail" runat="server" Text="Emailadres: "></asp:Label>
<asp:TextBox ID="txtmail" runat="server"></asp:TextBox>
<br />
<br />
<asp:Label ID="lblbericht" runat="server" Text="Bericht: "></asp:Label>
<br />
<br />
<asp:TextBox ID="txtbericht" runat="server" Height="200px" Width="750px"></asp:TextBox>
<br />
<br />
<br />
<asp:Button ID="btnVerzend" runat="server" Text="Verzenden" />
<br />
<br />
<br />
<asp:Label ID="lblres" runat="server" Text="Label" Visible="False"></asp:Label>
<br />
<br />
<br />
</td>
</tr>
</table>