How to setup SSL correctly on an erlang/ elixir server?

Question

I have a valid Let's Encrypt SSL certificate which works as expected when setup on windows IIS:

https://www.sslshopper.com/ssl-checker.html#hostname=https://paperlesssolutionsltd.com.ng

When I apply same certificate to an Elixir ACE server like so:

certfile: Application.app_dir(@app, "priv/cert.pem"),
keyfile: Application.app_dir(@app, "priv/cert.key")

I get the following errors:

https://www.sslshopper.com/ssl-checker.html#hostname=https://paperlesssolutionsltd.com.ng:8443

Please what does Erlang SSL config require in order to fix this?

Thanks!

Answer 1

Was an erlang issue!

Upgrading to OTP 23.2.4 helped.

Also I had to use a cert file that combined my cert and Lets-encrypt's intermediate file.

Set this to both :certfile and :cacertfile

All credit to @voltone (Bram Verburg)

https://elixirforum.com/t/making-ssl-tests-all-pass-for-phoenix-lets-encrypt/3507/30?u=charleso