It can due to the following causes:
Your language setting in PrestaShop is wrong. Your source language and your other languages are the same native language. For example, if your source language is Spanish International (ISO es-es) and you also have installed Spanish Mexican (ISO es-mx). In this case Glotio cannot translate them, because they are the same language.
The system only found one only language. To solve this problem you must install other languages in your store. More info: How to add a new language in your PrestaShop.
Your languages do not have a correct ISO code or that language cannot be translated with Glotio. To solve this problem you can try to install another language or contact us so we can study if we can add support for that language.