How to plot graph in market basket analysis while using grouped method?

library(arules)
library(arulesViz)
data("Groceries")
summary(Groceries)
rules1 <- apriori(Groceries, parameter = list(support = 0.002, confidence = 0.5, minlen = 5))
inspect(head(rules1,5))
plot(rules1)
plot(rules1, method = "grouped") ##I am getting error after running this code

**plot(rules1, method = "grouped")
Error in `levels<-`(`*tmp*`, value = as.character(levels)) : 
  factor level [9] is duplicated**