Error message on when charting efficient frontier in r studios

Question

When I run this line of code, I get the error message:

chart.RiskReward(maxret, risk.col = "StdDev", return.col = "mean",
                 chart.assets = "False")
chart.EfficientFrontier(maxret, match.col="StdDev", n.portfolios=100, type="l", tangent.line=FALSE)

Error in seq.default(from = minret, to = maxret, length.out = n.portfolios) :
  'from' must be a finite number