Hundreds of first-year students were set to write an “introduction to law” exam via the internet on Monday but an overloaded server made the task impossible for some.
Some students attempting to do the test on their computers were met with an error message after 11 minutes, the Neue Zürcher Zeitung (NZZ) reported.
The message said “access unavailable” and “the server is currently unable to handle the request”.
For many of the students it was the first test they had taken at the university, NZZ said.
The law faculty believed that having students write the exam at home on a computer avoided having to hold it in a crowded auditorium.
It is not clear how many students were affected by the server crash, the NZZ said.
When the decision to hold online exams was made it drew criticism from students and some professors.
“This form is not suited to test what they (students) have learned,” sociology professor Kurt Imhof earlier told weekly newspaper Schweiz am Sonntag.
Questions were also raised about the possibilities of cheating,
University authorities countered that students were to get the exam questions in a different order with time limited to 90 minutes to deter cheats.
A total of 780 new students were set to write the online exams on three different dates, with others set for Wednesday and Friday this week.
Students who did not initially pass the exam were to be able to take it again.
The university has not yet said what will happen to the online exams planned for the other two days.