Android does not download any files from untrusted CA certificate site I work on a site that serves mobile phones and shares some file. When I publish my site in http everything works great.

But when I activate SSL and publish my site via HTTPS with my own certificate, Android doesn't download any file from my site.

I create my own SSL CA certificate via openSSL in my local  PC and not purchasing from standard seller like GoDaddy.

How do I install my CA certificate to Android?

Do I have to purchase SSL from a standard seller to solve this issue?

My android version is 4.4.4.
You can install a CA certificate very easily through Settings.
Just go to Security-&gt;Install from SD and choose your certificate.
It will be installed to your device's certificate store/secured storage and should be used automatically by all applications that rely on that certificate store (which should be like every app that connects to the internet using SSL).

You can also look what certificates are currently installed in trusted certificates where they are split into User and System certificates.