Unbelievably unprofessional, no answer at all - neither by email or LinkedIn
Verbesserungsvorschläge
I'm personally a huge fan of the product (and paying user for months). Applied via email, contacted an HR person via LinkedIn and tried to call and finally even placed a support ticket - never received any answer whatsoever.
A polite notice (ideally by phone) that the company does not want to hire someone is fine.
A canned message that's clearly mass-sent by email is acceptable.
No answer whatever on multiple channels is UNPROFESSIONAL beyond belief. Considering this complete lack of respect and frankly behaving as a proper company should shows me that I would not want to work here.
Be grateful when someone applies and behave graciously and no reasonable person will take issue.
Act like this and you squander goodwill and reputation.