[Solved] ASP.Net Button Click event not firing (working)

Submit button is not working in code behind in my aspx.cs file

html

<div class="col-5">
    <div class="row" style="background-color:pink; font-size:20px; text-align:center; font-weight:bold;">
        <div class="col-12">User(s) Valuable Feedback/Suggestion Form :
            <i class="fa fa-comments" style="font-size:24px; color:Blue;"></i>
        </div>
    </div>
    <div class="row">
        <div class="col-4">User Full Name :<font style="color:Red;">*</font></div>
        <div class="col-7">
            <asp:TextBox ID="txtUname" runat="server" CssClass="textbox_Feedback" Placeholder="User Full Name" required></asp:TextBox>
        </div>
    </div>
    <div class="row">
        <div class="col-4">User Mobile No. :<font style="color:Red;">*</font></div>
        <div class="col-7">
            <asp:TextBox ID="txtMobile" runat="server" CssClass="textbox_Feedback" Placeholder="User Mobile No." MaxLength="10" required></asp:TextBox>
        </div>
    </div>
    <div class="row">
        <div class="col-4">User Email :<font style="color:Red;">*</font></div>
        <div class="col-7">
            <asp:TextBox ID="txtEmail" runat="server" CssClass="textbox_Feedback" Placeholder="User Email" required></asp:TextBox>
        </div>
    </div>
    <div class="row">
        <div class="col-4">Comment Type :<font style="color:Red;">*</font></div>
        <div class="col-7">
            <asp:DropDownList ID="ddlCommentType" runat="server" CssClass="DropDownList" required>
                <asp:ListItem Selected="True" Value="0">-Select-</asp:ListItem>
                <asp:ListItem Value="01">Feedback</asp:ListItem>
                <asp:ListItem Value="02">Suggestion</asp:ListItem>
            </asp:DropDownList>
        </div>
    </div>
    <div class="row">
        <div class="col-4">Rate Us By Star :<font style="color:Red;">*</font></div>
        <div class="col-7">
            <asp:DropDownList ID="ddlStar" runat="server" CssClass="DropDownList" required>
                <asp:ListItem Selected="True" Value="0">-Select-</asp:ListItem>
                <asp:ListItem Value="01">*</asp:ListItem>
                <asp:ListItem Value="02">**</asp:ListItem>
                <asp:ListItem Value="03">***</asp:ListItem>
                <asp:ListItem Value="04">****</asp:ListItem>
                <asp:ListItem Value="05">*****</asp:ListItem>
            </asp:DropDownList>
        </div>
    </div>
    <div class="row">
        <div class="col-4">Subject :<font style="color:Red;">*</font></div>
        <div class="col-7">
            <asp:TextBox ID="txtSub" runat="server" CssClass="textbox_Feedback" Placeholder="User Email" required></asp:TextBox>
        </div>
    </div>
    <div class="row">
        <div class="col-4">Write Something :<font style="color:Red;">*</font></div>
        <div class="col-7">
            <asp:TextBox ID="txtComment" runat="server" CssClass="textbox_Feedback" Placeholder="Your Valuable Feedback/Suggestions." TextMode="MultiLine" Height="80px" required></asp:TextBox>
        </div>
    </div>
    <div class="row">
        <div class="col-4">Attach a File :</div>
        <div class="col-7">
            <asp:FileUpload ID="FileUpload1" runat="server" />
            ext. - jpeg/jpg/png/pdf only.
        </div>
    </div>
    <div class="row">
        <div class="col-4"></div>
        <div class="col-7">
            <asp:Button ID="btnSubmit" runat="server" Text="Submit" CssClass="ButtonSave" OnClick="btnSubmit_Click" />
        </div>
    </div>
</div>

Code

protected void btnSubmit_Click(object sender, System.EventArgs e)
{
    //..........................Client Ip Address...........................................................
    string ipAddress = "";
    ipAddress = Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
    if (ipAddress == "" || ipAddress == null)
        ipAddress = Request.ServerVariables["REMOTE_ADDR"];
 
    //saving file in the physical folder;
    string virtualFolder = "~/Uploads/Feed_Sugg/";
    //Set file extension for Photo and sign
    string file_ext = Path.GetExtension(FileUpload1.PostedFile.FileName).ToLower();
    if (FileUpload1.HasFile)
    {
        if (file_ext == ".JPEG" || file_ext == ".jpg" || file_ext == ".png" || file_ext == ".bmp" || file_ext == ".pdf")
        {
            FileUpload1.SaveAs(Server.MapPath(virtualFolder) + "\\" + txtMobile.Text + "" + file_ext);
            string photo = txtMobile.Text + "" + file_ext;
            string physicalFolder = Server.MapPath(virtualFolder);
            //img_Photo.Visible = true;
            //img_Photo.ImageUrl = Server.MapPath(virtualFolder) + @"\" + lblCid.Text + "" + file_ext;
            //Save Commands Method.............................................................................
            cnn.Open();
            SqlCommand cmd = new SqlCommand("insert_Community_FeedSuggs", cnn);
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.AddWithValue("@UserId", SqlDbType.VarChar).Value = "";
            cmd.Parameters.AddWithValue("@UserIp", ipAddress);
            cmd.Parameters.AddWithValue("@CommType", ddlCommentType.SelectedItem.ToString());
            cmd.Parameters.AddWithValue("@iNetChannel", SqlDbType.VarChar).Value = "";
            cmd.Parameters.AddWithValue("@UserMobile", txtMobile.Text);
            cmd.Parameters.AddWithValue("@UserEmail", txtEmail);
            cmd.Parameters.AddWithValue("@TicketSubject", txtSub.Text);
            cmd.Parameters.AddWithValue("@RatingByUser", ddlStar.SelectedItem.ToString());
            cmd.Parameters.AddWithValue("@Comment", txtComment.Text);
            cmd.Parameters.AddWithValue("@ImgPath", SqlDbType.VarChar).Value = "";
            cmd.Parameters.AddWithValue("@ImgName", photo);
            cmd.ExecuteNonQuery();
            cnn.Close();
            {
                Page.ClientScript.RegisterStartupScript(this.GetType(), Guid.NewGuid().ToString(), "alert('Your. - " + ddlCommentType.SelectedItem.ToString() + " has been submitted successfully.');", true);
            }
        }
        else
        {
            Page.ClientScript.RegisterStartupScript(this.GetType(), Guid.NewGuid().ToString(), "alert('Only Images ('.JPG, .PNG .BMP and .pdf format') can be uploaded')");
        }
    }
}