[Решено] Getting language mapping errors

Background of the issue:
I have a website with German as a default language and French as a secondary language. I was trying to use automatic translations, but they stopped working.

Symptoms:
I am getting language mapping errors: 'FR: Content in this language cannot be automatically translated unless you map it to a supported language.' and 'DE: None of your content can be automatically translated until you map your default language to a supported language.' Re-saving the Languages table doesn't help.

Questions:
Why are automatic translations not working despite having language mapping set to French and German?
How can I resolve the language mapping errors for automatic translations?