Hi guys,
Help me out please. What does it mean if out of four reviewers, one reviewer marked my paper as "not acceptable"?
thanks

It means one reviewer hated it and the others, presumably, thought it was at least OK. What comments did the editor make? What do you think? Do you think the person who hated it made some reasonable points that you could use to improve your paper or do you think they were an idiot who didn't read it properly and you can refute pretty much everything they said with better explanations?

Editors usually go with majority opinion so you will probably be ok