The proper way to translate strings depends a lot on how they have been implemented inside the theme/plugin.
1. Please try this:
Go to WPML > String Translation and at the bottom of the page you will find a checkbox called "Look for strings while pages are rendered". You can enable (check) that and then go in the front end to a page where you have that string showing up and then go back to WPML > String Translation and search for that string and see if it now shows up.
2. If you can't find them inside the WPML > String Translation, they might be added as admin text.
PS: In our situation, Step 2 might be exactly what you are looking for. Follow the steps and search for that URL that you added in the theme settings and you should find the option to add it to WPML String Translation and then go to WPML > String Translation and translate it.
