Post back event does not fire after deployment

I have a dropdown list with a selected index changed and auto postback set to true inside an update panel. The event fires when I run it on my machine. But after deployment and accessing it through the web, the event doesn't fire. Below is the snippet of my markup:

<div>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:Timer ID="Timer1" runat="server"
Interval="240000" OnTick="Timer1_Tick">
asp:Timer>
<div class="row">
<div class="col-lg-2">
Teacher's name:
div>
<div class="col-lg-3">
<asp:DropDownList ID="ddlTeacherName" CssClass="form-control" DataTextField="FullName" DataValueField="TeacherID" runat="server" AutoPostBack="True" OnSelectedIndexChanged="ddlTeacherName_SelectedIndexChanged">asp:DropDownList>
div>
<div class="col-lg-2">
<asp:Label ID="lblTeacherID" runat="server" CssClass="form-control">asp:Label>
div>
div>
ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="Timer1" EventName="Tick" />
Triggers>
asp:UpdatePanel>
div>

Any help is very much appreciated.

2 Replies

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Francis Susaimichael8y ago
It may due to ASP.Net version upgrade. Try the below url:

https://forums.asp.net/t/1541905.aspx?Update+panel+not+working+for+drop+down+list
+1
Suthahar Jegatheesan8y ago
Hello ,
I guess is that the asp.net session cookie was not able to be saved, so the postback was not working after deployment .

can you try to change / add below code in web.config file

"true" />
+1