Mixed content warning on www.ads-software.com

Since a feed isn’t content inside your page, this is not a critical problem. You might still leave it as is, provided that the http protocol works well.
But: If requests to http are redirected to https, then it would of course be good to directly give a URL with the correct protocol prefix.

Now, this link may be put there by your theme or by some plugin. Since you don’t give any link to your site and don’t tell me what theme you’re using, I can’t give you any more detailed hints on this.

Possible ways to fix this:
1. Find out which template file is guilty sending out these links, set up a child theme and put a copy of this file in the child theme, after having changed http to https.
2. It might be possible to fix this by installing the plugin really-simple-ssl
I’m not sure, but you may try. This plugin will try to change all on-site links to https.
3. Your theme might allow you to turn OFF these links. If that’s the case, then you could simply add them semi-manually, say with a plugin that will inject things you need inside the head tags.

Good luck. Let me know how you get along.