I make in master page UpdatePanel
<asp:Timer ID="Timer1" runat="server" Interval="3000" OnTick="Timeradmin_Tick">
</asp:Timer>
<asp:UpdatePanel ID="UpdatePanel5" runat="server" UpdateMode="Conditional" ChildrenAsTriggers="true">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="Timeradmin" EventName="Tick" />
</Triggers>
<ContentTemplate>
<asp:Label ID="LabelEmail" runat="server" ...
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