Can't Load Utility Website

I am trying to load my utility website to make a payment and view my bill but I keep getting the ERR_TIMED_OUT error. I've checked with my utility company and they have no issue loading the website and only other people who have AT&T have had this issue loading the website. I am so confused as to why I am having this issue, it is only this one website that does not load. What strange is that this used to load with no issue and all of a sudden it's an issue and now I can't pay my bill like I used to. 

Website: https://lancasteroh.authoritypay.com/