Onclick button doesnt fire when click - asp.net

Question

this is code below that doesnt work, i try work with seperate solution with same database but this problem seems hard to solve. thanks in advance
<div class="section-title">
<h2>Register <span>Now</span></h2>
<p>Ut possimus qui ut temporibus culpa velit eveniet modi omnis est adipisci expedita at voluptas atque vitae autem.</p>
</div>
<div class="php-email-form">
<div class="row">
<div class="col-lg-4 col-md-6 form-group">
<asp:TextBox ID="TextBox1" runat="server" type="text" class="form-control" placeholder="Your ID Number" data-rule="minlen:8" data-msg="Please enter at least 8 chars" ></asp:TextBox>
<div class="validate"></div>
</div>
<div class="col-lg-4 col-md-6 form-group mt-3 mt-md-0">
<asp:TextBox ID="TextBox2" runat="server" type="text" class="form-control" placeholder="Username" data-rule="minlen:4" data-msg="Please enter at least 4 chars" required="required"></asp:TextBox>
<div class="validate"></div>
</div>
<div class="col-lg-4 col-md-6 form-group mt-3">
<asp:TextBox ID="TextBox3" runat="server" type="password" class="form-control" placeholder="Password" data-rule="minlen:4" data-msg="Please enter at least 4 chars" required="required" ></asp:TextBox>
<div class="validate"></div>
</div>
<div class="col-lg-4 col-md-6 form-group mt-3 mt-md-0">
<asp:TextBox ID="TextBox4" runat="server" type="email" class="form-control" placeholder="Your Email" data-rule="email" data-msg="Please enter a valid email"></asp:TextBox>
<div class="validate"></div>
</div>
<div class="col-lg-4 col-md-6 form-group mt-3 mt-md-0">
<p>Register As</p>
<asp:DropDownList ID="DropDownList1" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" Height="50px" Width="329px" Font-Size="Medium" Font-Names="Arial" Font-Italic="True">
<asp:ListItem></asp:ListItem>
<asp:ListItem>Employee</asp:ListItem>
<asp:ListItem>Customer</asp:ListItem>
</asp:DropDownList>
<div class="validate"></div>
</div>
</div>
<div class="form-group mt-3">
<asp:TextBox ID="TextBox7" runat="server" class="form-control" rows="5" placeholder="Address" Width="1119px"></asp:TextBox>
<div class="validate"></div>
</div>
<asp:Button ID="Button3" runat="server" OnClick="Button1_Click" Text="Register" />
<div class="text-center">
</div>
</div>
</div>
</section>**strong text**
but this code below work, idk what the problem, its just same code with/without design
<div>
<div style="font-size:x-large; text-align:center">Register</div>
<table class="nav-justified">
<tr>
<td class="modal-sm" style="width: 290px">ID</td>
<td>
<asp:TextBox ID="TextBox1" runat="server" Width="243px"></asp:TextBox>
</td>
<td> </td>
</tr>
<tr>
<td class="modal-sm" style="width: 290px">Username</td>
<td>
<asp:TextBox ID="TextBox2" runat="server" Width="243px"></asp:TextBox>
</td>
<td> </td>
</tr>
<tr>
<td class="modal-sm" style="width: 290px">Password</td>
<td>
<asp:TextBox ID="TextBox3" runat="server" Width="243px"></asp:TextBox>
</td>
<td> </td>
</tr>
<tr>
<td class="modal-sm" style="width: 290px">Email</td>
<td>
<asp:TextBox ID="TextBox4" runat="server" Width="243px"></asp:TextBox>
</td>
<td> </td>
</tr>
<tr>
<td class="modal-sm" style="width: 290px">Register as:</td>
<td>
<asp:DropDownList ID="DropDownList1" runat="server">
<asp:ListItem></asp:ListItem>
<asp:ListItem>Employee</asp:ListItem>
<asp:ListItem>Customer</asp:ListItem>
</asp:DropDownList>
</td>
<td> </td>
</tr>
<tr>
<td class="modal-sm" style="width: 290px">Address</td>
<td>
<asp:TextBox ID="TextBox7" runat="server" Width="243px"></asp:TextBox>
</td>
<td> </td>
</tr>
<tr>
<td class="modal-sm" style="width: 290px"> </td>
<td>
<asp:Button ID="Button1" runat="server" BackColor="#CCCC00" BorderColor="#FF3300" Font-Bold="True" ForeColor="#FF9900" OnClick="Button1_Click" Text="Register" />
</td>
<td> </td>
</tr>
</table>
<br />
Log In
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
<br />
<br />
</div>
and these both codes share same aspx.cs buttons click function but it still doesnt fire and idk know why, i keep writing this because i cant submit questions otherwise

Answer 1

I think it's because of this line of code:
<div class="validate"></div>
Try to avoid validation by changing CausesValidation attribute to false in the button element:
CausesValidation="false"