WestJet Airlines Ltd. (WJA.TO) said Tuesday afternoon that its website is up and running again, after a temporary system outage prompted a number of customers to complain about problems accessing the company’s online reservation and check-in system.

The Calgary-based airline said in an emailed statement to BNN Bloomberg that a “brief system-wide infrastructure outage” with one of its vendors affected multiple WestJet systems earlier on Tuesday morning.

“As we work to resume normal operations, we encourage guests to check their flight status and arrive early due to earlier delays with the check-in process and kiosks at the airport,” WestJet spokesperson Morgan Bell said in an email.

“We thank all guests for their continued patience and apologize for any inconvenience this may have caused.”

A number of customers took to Twitter to air their frustrations during WestJet’s outage. One customer said he was trying to book flights to take advantage of WestJet’s one-day sale, but both the airline’s website and app were having issues.