Problems with LanguageTool App

A friend of mine uses the LanguageTool-App for Android (apk from 2018) for spell checking and grammar correction on her Fairphone3 and FP5. Not as add-on in Browser!
Since two days the app doesn’t work anymore.
Does anyone here use this app, too, and maybe has some ideas?

Do you have suggestions for offline spell checking and grammar correction to be used on /e/?

Regain your privacy! Adopt /e/OS the deGoogled mobile OS and online servicesphone