Periodically cannot access Purpleair web domains

Hi, my organization occasionally loses connection to purpleair’s web domains, including the API’s. When this happens, we cannot browse to the website or, we get a “refused to connect” browser error. We can however, reach

When this happens, it seems to be temporary, lasting for a day or two. The most recent disconnect, started on 10/30 some time between 7PM and 8PM CDT. Our organization’s IT group is not able to figure out why the PA domains refuse to connect like this on our statewide internet network.

Anyone else experiencing this?