2 data sources - How to Catch ERROR dynamically and and execute alternative query?

Hi guys,

I am new to M Code and I was wondering if anyone could give me a help. 

I wrote the code below to connect to a data source and look for the column "ForexExchange". If the column is not found the ERROR should be caught and it should connect to a second data source to extract the information from there.

let
    get_bidAsk = (file as text) =>
let
    Source = Web.Page(Web.Contents(file)),
             Data3 = Source{3}[Data],
	     #"Changed Type" = Table.TransformColumnTypes(Data3,{{"", type text}, {"ForexExchange", type text}, {"Last", type number}, {"Bid", type number}, {"Ask", type number}, {"Volume", type number}, {"Change %", Percentage.Type}, {"Currency", type text}, {"Time", type time}, {"2", type text}}),
										
    TestForError = try Source,
	   
    Output = if TestForError[HasError] then 
                 get_soleBidASK(file)
             else 
                 #"Changed Type" = Table.TransformColumnTypes(Data3,{{"", type text}, {"ForexExchange", type text}, {"Last", type number}, {"Bid", type number}, {"Ask", type number}, {"Volume", type number}, {"Change %", Percentage.Type}, {"Currency", type text}, {"Time", type time}, {"2", type text}}),
                 #"Removed Columns" = Table.RemoveColumns(#"Changed Type",{""}),
		 #"Reordered Columns" = Table.ReorderColumns(#"Removed Columns",{"ForexExchange", "Last", "Bid", "Currency", "Ask", "Volume", "Change %", "Time", "2"}),
		 #"Removed Columns1" = Table.RemoveColumns(#"Reordered Columns",{"2"})					
in
    Output
in
    get_bidAsk

This is print ERROR I get from the function output. 

It connects to the first data source and doesnt find the column "ForexExchange". I would need it to identify the ERROR using the try<> and then connect to the second datasource to extract the records there.

Thanks