I think Yahoo Finance updated their financial statement page, and code is not working any more. I think the "xpath" has changed and "p" is returning a list of zero. I can't find the "table" tag in the HTML code to update the xpath link.
# Collect the Income Statement data
link <- "https://finance.yahoo.com/quote/"
link <- paste0(link, stock[i], "/financials?p=", stock[i])
wahis.session <- html_session(link)
p <- wahis.session %>%
html_nodes(xpath = '//*[@id="Col1-3-Financials-Proxy"]/section/div[3]/table')%>%
html_table(fill = TRUE)
IncomeStatement <- p[[1]]