Hello Peter,

90 seconds is the default AsyncPostBackTimeOut property value of
ScriptManager. To solve the problem, we can increase the timeout by adding
the property AsyncPostBackTimeOut to the script manager:

<asp:ScriptManager ID="ScriptManager1" runat="server"
AsyncPostBackTimeOut="600" >
</asp:ScriptManager>

Please have a try and let me know if it works for you.

Regards,
Jialiang Ge (jialge@online.microsoft.com, remove 'online.')
Microsoft Online Community Support

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Server.ScriptTimeout = aNumber

there is no reliable way to have the browser wait 5 minutes for a response. a
server push might work, you turn off buffering and send a bit of data and a
flush every second.

a better approach is to queue the report and poll for completion.

-- bruce (sqlwork.com)