On controls panel the date filter controls is erroring out

As you can see with my image I have the 'month' filter on my controls filled in with some date. It keeps erroring out with [esaggs]>. The 'month' field is the time field on my index pattern. When I check my dev tools it says it's a 400 error. I'm not sure how to go about and fix this.

FYI: the other controls work just fine for me.

Need some help.