CHICAGO (CBS) — On the same day fare hikes went into effect for Metra, the Ventra app that normally allows riders to buy tickets on their smart phones and tablets malfunctioned for a few hours Thursday morning.

Rather than buying paper tickets at stations, Metra customers can buy electronic tickets on the Ventra app, and show them to conductors on the train. However, the app was crashing Thursday morning when users tried to purchase new tickets. Previously purchased tickets were still working.

Metra spokesman Michael Gillis said the problem started sometime Thursday morning, as a fare hike was going into effect. Ventra officials said the problem was fixed by about 10:20 a.m.

While the app was malfunctioning, riders who had already purchased fares — including 10-ride and monthly passes — could still use those tickets, but couldn’t purchase new fares. Some riders complained on Twitter that conductors were forcing them to pay the $5 surcharge for buying a paper ticket on the train, even though the Ventra app wasn’t working.

The price of one-way tickets on Metra rose by 25 cents in all zones for Metra riders on Thursday. Ten-ride tickets jumped $4.25 to $7.75 per ticket, depending on the zone. Monthly fares – the most popular ticket for riders – went up between $9 and $12.50 per ticket, also depending on the zone. Tickets for unlimited rides on the weekends went up from $8 to $10.