Hi I am new to forecasting. I am trying to do a hierarchical forecast using the HTS package. I have created two hierarchies. And then I applied below

forecast_middle_out_lum_arima<-forecast(train_hierarchy_lumpy,h=7,method = “mo”,fmethod = “arima”,level = 1)

accuracy(forecast_bottom_up_lum_arima,test_hierarchy_lumpy,levels = 2)

I keep getting this error

Error in base::colMeans(x, na.rm = na.rm, dims = dims, …) :
‘x’ must be an array of at least two dimensions

I am not sure what is happening. My dataset is only for one and I am trying to create a weekly forecast. Can someone please explain what I am doing wrong here

Thank you

I have tried multiple things but I seem to keep getting this error