CUConnect, the online University of Colorado portal that allows students and faculty to access course schedules and student rosters, is back up after not working for most of Monday, the Boulder campus' first day of classes.

CU spokeswoman Malinda Miller-Huey said the system began working again at around 3 a.m. Tuesday.

Problems with the portal were caused by a software patch installed several weeks ago to correct a vulnerability in the CUConnect software, said Greg Stauffer, spokesman for the university’s information technology services office. 

The office had tested the patch, Stauffer said, and it did not present any problems — that is, until CUConnect started to experience “peak loads” on Sunday night, the eve of the first day of classes.

CUConnect worked only intermittently on Monday, causing frustration among students and making for a busy day in the registrar’s office, which scrambled to help students find their classes and add or drop courses.

Students use CUConnect to register for classes, view their schedules and other student services. Professors use the portal to access course tools such as rosters and class e-mail.

At around noon Tuesday, the CUConnect Web site reported that the portal was “currently experiencing high load.”