Spellcheck in localserver

I have a local setup of languagetool (HTTP Server - LanguageTool Wiki)
Using the API that it exposes, I use the ‘/v2/check’ path to get details about a text. Even if I pass the sample text provided on the languagetool homepage the spelling errors are not detected. The work “detecd” is not returned for spelling error.

What am I missing here ?

What do you use as a language code? en will not give you spelling errors, you need to use en-US etc. for that.