input data must be numeric

Question

I am trying to calculate tumor growth rates with the tumgr package using the attahced dataset

library(readxl)
 sampleData <- read_excel("C:/Users/user/Downloads/sampleData.xlsx")
 View(sampleData)
install.packages("tumgr")
 library(tumgr)

 par(mfrow=c(3, 2))
 out <- gdrate(sampleData, 0.05, TRUE)

inputprep(input) error: all input data must be numeric

But all data is numeric, so I cannot find how to solve this. Can you help me? I expect output on growth rate