"The certificate chain was issued by an authority that is not trusted" - Error when using RVest

I am trying to scrape a website with the html_session() function of the rvest package. When I try to acces the website (a local proxy authentication website), I get this error:

Error in curl::curl_fetch_memory(url, handle = handle) : 
  schannel: next InitializeSecurityContext failed: SEC_E_UNTRUSTED_ROOT (0x80090325) - The certificate chain was issued by an authority that is not trusted.

It OK that such an error message arises, as there are certificate issues when accesing the website with a standard browser such as Chrome or Firefox. Nevertheless, how can I override this situation and continue browsing with rvest?

(maybe something related to this may help: "The certificate chain was issued by an authority that is not trusted" when connecting DB in VM Role from Azure website).

Thanks!