Can you please check below points
1) check the time out value in web.config
<authentication mode="Forms">
<forms loginUrl="Users_Login.aspx" timeout="555555555"/>
</authentication>
2) can you also verify on clicking on the button if authentication exists for the user. Like are you still getting is authenticated as true
3) Further you can write some thing like below code to check what exactly is the reason for the error
Protected Sub ScriptManager1_AsyncPostBackError(ByVal sender As Object, ByVal e As Microsoft.Web.UI.AsyncPostBackErrorEventArgs) Handles ScriptManager1.AsyncPostBackError
Dim conn As New SqlConnection
Try
conn.ConnectionString = ConfigurationManager.ConnectionStrings("ApplicationDatabase").ConnectionString
Dim comm As SqlCommand = conn.CreateCommand
comm.CommandText = "AjaxRecordError"
comm.CommandType = CommandType.StoredProcedure
comm.Parameters.AddWithValue("exMessage", e.Exception.Message)
comm.Parameters.AddWithValue("exStack", e.Exception.StackTrace)
comm.Parameters.AddWithValue("exSource", e.Exception.Source)
comm.Parameters.AddWithValue("exServerName", Server.MachineName)
comm.Parameters.AddWithValue("date", DateTime.UtcNow)
comm.Parameters.AddWithValue("ip", Request.UserHostAddress)
conn.Open()
comm.ExecuteNonQuery()
Catch ex As Exception
Finally
conn.Close()
End Try
Please let us know the result or in case you find any other possible solution as well....
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