How do I use rvest to sort text into different columns?

I am using rvest to (try to) scrape all the author affiliation data from a database of academic publications called RePEc. I have the authors' short IDs, which I'm using to scrape affiliation data. However, each time I try, it gives me the 404 error: Error in open.connection(x, "rb") : HTTP error 404

It must be an issue with my use of sapply because when I test it using an individual ID, it works. Here is the code I'm using:

df$author_reg <- c("paa6","paa2","paa1", "paa8")

df$websites <- paste0("https://ideas.repec.org/e/", df$author_reg, ".html")

df$affiliation <- sapply(df$websites, function(x) try(x %>% read_html %>% html_nodes("#affiliation h3") %>% html_text()))

I actually need to do this for six columns of authors and there are NA values I'd like to skip so if anyone knows how to do that as well, I would be enormously grateful (but not a big deal if I not). Thank you in advance for your help!