I just tested your website and it loads up just fine for me.
I will also attach a screenshot below.
That error is the default WordPress error when the platform can't connect to the database. Usually, it is a short time error that's related to the site's hosting most of the time and I think that you might have been seeing that for a couple of minutes.
Also, make sure that you are not seeing a cached version of your site so make sure that you visit it from an incognito browser window.
Please let me know if it shows up good for you, too.