There is an issue currently (2018-01-20) with the mediacom DNS servers. This may be contributing to your issue. They are working on resolving it.
I just tried it, and it works for me. Today is Jan 20, 2018.
Their website should be up and running as of 2018. Your browser may not be able to properly run the site. I would suggest changing browsers or using the showtimes from Google.
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