Does https://valid-isrgrootx1.letsencrypt.org/ work for you? If not, your system might not trust ISRG Root X1 (which it should, if Windows updates are enabled).
This post could also help:
Does https://valid-isrgrootx1.letsencrypt.org/ work for you? If not, your system might not trust ISRG Root X1 (which it should, if Windows updates are enabled).
This post could also help: