The possible reasons a buy limit order wasn't executed are:
- You were buying the trade, thus you need to focus on the Ask Price.
- Charts only show the historical Bid price by default.
- Ask price is always higher than the Bid price as Ask Price = Bid Price + Spread.
Thus, even on the chart, you could see the price reaching your requested price level, the Ask price was indeed higher, and not that the Ask price was reached.