Grant for the Web uses createsend.com to capture email addresses for updates. Unfortunately, this domain appears on blacklists, namely https://hosts-file.net/ad_servers.txt, so any device configured using this blacklist will block it (e.g., Pi-hole).
While the email sign-up widget script loads (from a separate subdomain), it doesn’t seem to account for the possibility of request failure. So in this situation clicking the button does nothing. There is no error message or similar.