[Закрытые] String translation doesn't work and layout part translation

Background of the issue:
I have two issues on my website скрытая ссылка where I can't make the translation work. The first issue is with the string 'Related post' which is translated into Danish and Spanish. It worked earlier but now it doesn't work on my Spanish version. The second issue is with translating a layout part. I have a post translated into English and need it translated into Spanish. When I translate the post into Spanish, the layout part is not translated or visible. I have followed the instructions here https://wpml.org/forums/topic/translation-of-layout-parts-themify/ but the layout part is not shown in the Themify strings.

Symptoms:
The string 'Related post' is not working in the Spanish version. The layout part is not translated or visible in the Spanish version of a post.

Questions:
Why is the string 'Related post' not working in the Spanish version?
How can I translate the layout part into Spanish?