In same cases appear the following error during GET or POST operations to an HTTPS site using wget.

# wget  https://<URL>/seadragon-min.js
--2014-11-26 09:30:14--  https://<URL>/seadragon-min.js
Resolving <URL> (<URL>)... <IP>
Connecting to <URL> (<URL>)|<IP>|:443... connected.
ERROR: The certificate of `<URL>' is not trusted.
ERROR: The certificate of `<URL>' hasn't got a known issuer.
  1. Workaround: Using the option --no-check-certificate wget will not check the certificate
  2. If from another machine seems that it works, try to install CA-CERTIFICATE
    1. # apt-get install ca-certificates