Make sure your material is absolutely flat against the bed. Even the tiniest bit of warp can cause it not to cut through. These are a big help: Honeycomb bed holdown pins, and/or magnets, if you have some.
Also, for future reference, posting in this category opens a support ticket as well. If you do both (email and post here) it can actually slow things down. My advice is opt for posting, since there are lots of experienced users around even after hours / on weekends who are always willing to lend a hand!