In the future, please don't assume the users or browsers are to blame and research the issue before answering.

I spoke with support this morning about this error. I have cleared my browser cache, deleted temporary internet files, switched to different browsers, and even went incognito. None of those worked. I was told it's happening in the US and UK as well. 

For those of you experiencing issues, you can change the dates manually to get the reporting period you want, you just can't customize by customer or class unless you've saved a report with the same perimeters.