Symbols.GetSymbol not working, returning "symbol not found"

Hi,

So Im trying to write a bot that will monitor indicator values on two or three different markets. When I try to run optimization, I get this error:

Following code is in my bot:

foreach (Symbol symbol in Symbols.GetSymbols("USDCHF", "EURUSD", "AUDCAD"))
{
    Print(symbol.Name);
}

I add EURUSD instance to my bot, then select 250 tick timeframe and run the optimization. All results return 0. What is wrong here?