What browsers have you tested this with?
Is this across multiple devices, or with a single device?
I had a similar issue a while back with another site- I found that it was a browser settings issue issue.
being that this site works with a VPN i suspect a crappy ISP DNS resolver.
you can test 2 ways, either...
open a command prompt and type...
ping arcadecontrols.com
it should start returning replies from the site ip address 74.208.43.115. if it does not reply or it times out... type...
ping 74.208.43.115
you should get replies now.
OR you can test by...
open your web browswer and type in "arcadecontrols.com" if it fails, try typing in 74.208.43.115 (arcadecontrols network IP address)
in either case...if you can connect to the ip address but not the URL, change your DNS. your ISP DNS resolver has something messed up. change to cloudflares 1.1.1.1 (1.0.0.1 secondary) or googles 8.8.8.8 (8.8.4.4 secondary) you should change your DNS anyway. ISP's are notorious for blocking stuff and saying they don't and they will also store where you go, cloudflare does not. (google does track, but you can go in your google account and set it to purge it on the regular automatically.)