It appears the Sierra Chart website has been down for at least the last few hours.
Inconvenient when programming in ACSIL on a Sunday afternoon!
Ordinarily all support happens through the website, so I don't even know how to let them know about the problem.
Does anyone know their direct email?

I'm not trading live so, for me, it's just a data recording issue, but you may want to contact your broker and see if they have a means to contact them.

Also not trading live yet, will be testing & practicing for another few months before opening a brokerage account ...