Keep Bootstrap modal open when captcha validation fails in ASP.Net

hi

I refer below thread

Keep Bootstrap modal open if validation error is raised using jQuery in ASP.Net

I did it and it just worked for  requiredfieldvalidator but I use captcha code in page too

here in this div visible= false if users enter security code wrong it will show message in this div but here when I enter security code wrong and click button it closes Modal.

below are codes:

<div id="captchaE" class="attenCC1M" runat="server" visible="false">
    <asp:Label ID="Label46" runat="server" CssClass="lblattenCC1M">please enter sequrity code correctly</asp:Label>
    <asp:Image ID="Image11" runat="server" CssClass="imgattenM" ImageUrl="~/Image/main/atten.png"></asp:Image>
</div>

    protected void Imgsend_Click(object sender, ImageClickEventArgs e)
    {
 
        if (txtStopSpam.Text == ViewState["spam"].ToString())
 
        {
            captchaE.Visible = false;
            using (SqlConnection conn = General.GetConnection())
            {
                using (SqlCommand _cmd = General.GetCommand("MessageNew_insertInfo", conn))
                {
                    conn.Open();
 
                    _cmd.Parameters.AddWithValue("@Topic", Txttopic.Text);
                    _cmd.Parameters.AddWithValue("@Name", Txtname.Text);
                    _cmd.Parameters.AddWithValue("@Description", Txtdes.Text);
                    _cmd.Parameters.AddWithValue("@Tell", Txtmobile.Text);
                    _cmd.Parameters.AddWithValue("@email","");
                    _cmd.ExecuteNonQuery();
                }
            }
            generateStopSpamText();
        }
 
        else
        {
            captchaE.Visible = true;          
        } 
    }

could you help me?

Best regards

Neda