Apparently, my corporate web filter blocked the imcdb.org and www.imcdb.org due to othermalware:

"URL: GET http://imcdb.org/
Category: Transportation
Reason: BLOCK-MALWARE
Threat Type: othermalware
Threat Reason: Domain reported and verified as serving malware. Identified as malicious IP. Identified as malicious domain or URL.
Notification: WBRS"

I'll ask my co-worker to see which one is interfering the web filter.