In order to better comply with the University Computing Services' Foundational Security Controls, PSE inpects certain encrypted connections for information leakage (think: phishing links) and virus/malware downloads.
As a result, certain https links will not work without downloading a "root certificate". You can download it from here:
http://128.119.70.251:4126/certportal
Note that this is the same certificate used to verify your wireless connection, which means that if you are using the Conte wireless network, you are all set.