Paydro has a full entry management solution built in, for free.
From the event overview page find and click your event.
From the event menu click tools > click on Ticket scanner
Dependng on your needs you can use the iOS or Laptop scanner
Entry management just can't fail
The show must go on. Even without internet. Both the iOS & the laptop scanner work without internet. Once all attendees are loaded you are guarenteed you can scan the barcodes on the tickets.