An investigation is underway after a system-wide problem briefly closed TransLink's fare gates Friday. 

The hiccup wouldn’t let passengers use their Compass Cards to tap in or out of the system for roughly 20 minutes in the early afternoon.

The cause has yet to be confirmed.

“We’re in the early stages of our investigation,” TransLink said in a statement. “It appears that the closure may have been caused by staff.”

The issue hit just days before the next major step in the transit provider’s Compass rollout; TransLink is scheduled to close off its remaining fare gates on Monday.

“We can assure our customers that we are confident that the Compass system is working and that we are still ready to begin full gate closures,” TransLink said.

Fare gates can be opened either on site or remotely in the case of an emergency, the transit provider added. Staff opened access doors until Friday’s problem was resolved to let riders exit stations.