When numClients reached nodejs app crashs

[AdamSEY]

/folder/socketRTC/node_modules/socket.io-p2p-server/index.js:31
        var emittedOffer = {fromPeerId: socket.id, offerId: offerObj.offerId, offer: offerObj.offer}
                                                                     ^

TypeError: Cannot read property 'offerId' of undefined

That happens whenever numClients is over 5, also is there's any way to control numClients from
the server rather than the client?