Problem scenario
You run curl commands, but you keep getting this error "Client sent an HTTP request to an HTTPS server." What should you do?
Possible Solution #1
Use https instead of http. See this for more information.
Possible Solution #2
The "problem" is not actually a problem or a true error message. Some web servers have nothing but this as text. This is a sign that the web server is working correctly and the curl command was successful.
Possible Solution #3
Are you using Caddy and Nginx Proxy Manager? Can you not use Caddy and Nginx Proxy Manager (per https://vaultwarden.discourse.group/t/i-get-a-client-sent-an-http-request-to-an-https-server-error-on-all-pages/2296) at the same time?
Possible Solution #4
Are you using Go instead of just curl? If so, see https://github.com/golang/go/issues/49310