Do not work
When you say the words ‘do not work’ you could be trying to tell someone that they should not be working. As in, ‘do not go to your job today’, or ‘stay at home’. But the grammar here does not make any sense if you are trying to tell someone that a vending machine does not work.
If you were to put a sign on a vending machine you would most likely write the words ‘doesn’t work’ or even ‘out of order’. But we think that the latter would be asking a lot from this person. Whoever wrote this sign should really go back to school and take an English language exam.