Yesterday, suddenly, I could not render my Quarto book. I got the same error message after installing a new Quarto book from scratch. I also got the error message when checking Quarto in the terminal:
Checking R installation...........Fehler in curl_fetch_memory(r_svn_url(), handle = h) : Could not resolve host: svn.r-project.org Ruft auf: <Anonymous> ... r_versions -> r_versions_fetch -> curl_fetch_memory Ausführung angehalten [✓] Checking R installation...........(None) Unable to locate an installed version of R. Install R from https://cloud.r-project.org/
Trying to solve the problem by re-installing R, I noticed that about the same time as my problem appeared, the CRAN server in Vienna went down. So I did not change anything. Today CRAN is working again, and my issue disappeared. Coincidence or is there some dependency?