ASP.Net GridView pager is not displaying

I am having issue when i try to click on next button on any grid, page buttons disappears

page button next missing in first table

please fix

HTML

<form id="form1" runat="server">
    <div class="container">        
        <section class="main">
            <%--Css-Class="checkbox-group--%>
            <!-- Filters Section -->
            <section class="fltr" id="filtersection">
                <div class="filters">
                    <div class="filter-group">
                        <asp:TextBox ID="txtStartDate" runat="server" CssClass="datepicker" Placeholder="Start Date" TextMode="Date"></asp:TextBox>
                        <asp:TextBox ID="txtEndDate" runat="server" CssClass="datepicker" Placeholder="End Date" TextMode="Date"></asp:TextBox>
                    </div>
                    <div class="filter-group">
                        <label for="websiteList">Site:</label>
                        <asp:DropDownList ID="ddlSites" runat="server">
                        </asp:DropDownList>
                    </div>
                    <asp:Button ID="applyFilters" CssClass="button" runat="server" Text="Apply Filters" OnClick="applyFilters_Click" OnClientClick="drawChart()" />
                </div>
            </section>
            <div class="cards">
                <div class="card">
                    <h4>Total Sales</h4>
                    <asp:Label ID="totalSales" runat="server" Text="$0"></asp:Label>
                </div>
                <div class="card">
                    <h4>Orders</h4>
                    <asp:Label ID="ordersCount" runat="server" Text="0"></asp:Label>
                </div>
                <%-- <div class="card">
<h4>New Customers</h4>
<asp:Label ID="newCustomers" runat="server" Text="0"></asp:Label>
</div> --%>
                <div class="card">
                    <h4>Top Product</h4>
                    <asp:Label ID="topProduct" runat="server" Text="Product"></asp:Label>
                </div>
            </div>
            <!-- Sales Section with Charts -->
            <section class="sales" id="sales">
                <div class="sales-list">
                    <h1>Sales Overview</h1>
                    <!-- Canvas elements for charts -->
                    <div id="column_chart" style="width: 90%; height: 500px;"></div>
                    <div id="line_chart" style="width: 90%; height: 500px;"></div>
                </div>
            </section>
            <!-- Customers Section -->
            <section class="customers" id="customers">
                <div class="customer-list">
                    <h1>Customer List</h1>
                    <div class="customer-grids">
                        <asp:GridView ID="customerGridView" runat="server" AutoGenerateColumns="False" CssClass="table"
                            AllowPaging="True" PageSize="10" OnPageIndexChanging="customerGridView_PageIndexChanging" OnDataBound="customerGridView_DataBound">
                            <Columns>
                                <asp:BoundField DataField="name" HeaderText="Name" />
                                <asp:BoundField DataField="Email" HeaderText="Email" />
                                <asp:BoundField DataField="TotalOrderCount" HeaderText="Total Orders" />
                            </Columns>
                            <PagerSettings Mode="NextPrevious" PageButtonCount="4" PreviousPageText="Previous" NextPageText="Next" />
                        </asp:GridView>
                        <asp:GridView ID="CustomerGridViewcouponcount" runat="server" AutoGenerateColumns="False" CssClass="table"
                            AllowPaging="True" PageSize="10" OnPageIndexChanging="CustomerGridViewcouponcount_PageIndexChanging" OnDataBound="CustomerGridViewcouponcount_DataBound">
                            <Columns>
                                <asp:BoundField DataField="name" HeaderText="Name" />
                                <asp:BoundField DataField="Email" HeaderText="Email" />
                                <asp:BoundField DataField="CouponUsageCount" HeaderText="Coupon Usage Count" />
                            </Columns>
                            <PagerSettings Mode="NextPrevious" PageButtonCount="4" PreviousPageText="Previous" NextPageText="Next" />
                        </asp:GridView>
                    </div>
                </div>
            </section>
        </section>
    </div>
</form>