CHICAGO (CBS) — Some Chicago Fire Department promotional exams have been canceled this week due to computer problems with the third-party vendor that administers the test.

The gaffe could cost Chicago taxpayers big bucks.

READ MORE: Two Chicago Police Officers Shot On South Lawndale Released From Hospital

The Fire Department confirmed Tuesday night that there were major problems with the Fire Department lieutenant and battalion chief tests.

On Monday and Tuesday, technical problems with computers caused long delays.

Battalion chief tests scheduled for Wednesday have been canceled by the vendor, Fire Department spokesman Larry Langford said.

READ MORE: Chicago Weather: Warming Trend Continues, 80s By End Of Week

Langford said the city is proactively working with the vendor – which the city has been using for years – to address the issues.

Firefighters scheduled to take the battalion chief test on Wednesday were notified Tuesday night that the test is canceled.

Those who were to sit for the exam will be notified of when the test will be rescheduled, Langford said.

This could cost taxpayers money, because those taking the test get days off from the firehouse – and those positions need to be filled with firefighters making overtime.

MORE NEWS: MISSING: Kyrin Carter, 12, Has Autism, Last Seen At Best Western In Hammond, Indiana

Sources also told CBS 2 the issue could end up in a lawsuit.