We have a event created, where the maximum participants are set to 120. But since a single participant can buy a multiple ticket, I am not able to find a way to limit ticket to be sold to 120.
You can use price sets to track purchased tickets instead of just registrants.
See this reference (down the page to 'complex event fees with price sets'
I had written a comment to set the max participants in the Event settings , but you have already done that. So, never mind.