For the Renko chart to display correctly, it is important to select the appropriate box size. If the Renko chart is not displayed, most likely you have chosen a box that is too large for the current symbol.
You can change the box size in the chart Settings manually or select the ATR method of assigning the box size.
ATR means that the box size is calculated automatically by using the Average True Range (ATR) indicator. In Chart Properties, you can specify the bars back length, which will be used as ATR input value.