After going down Thursday, New Jersey Transit’s MyTix app was back up and running for Friday’s morning commute.

The agency has responded individually to complaints and apologized for an inconvenience.

Commuters reported being unable to log in, being charged more than once for tickets that didn’t process and being unable to view departure schedules. Some said they were denied entry on buses and trains because the app couldn’t produce their tickets.

NJ Transit said customers who had to pay for tickets that they already purchased can call 973-491-8810 to request a refund.

In addition to the app issues, several NJ Transit buses didn’t run Thursday due to “operational issues,” and at least one train got stuck out of New York Penn Station overnight, causing minor delays.

For the last several days, NJ Transit has been forced to cancel trains because engineers did not show up to work, taking advantage of a schedule change clause in their contracts.

Gov. Chris Christie said Thursday that he will take "every action that is necessary" to make sure NJ Transit train engineers show up for work.