Server downtime

I am using a nodejs express app with a domain protected by cloudflare, I setup uptimerobot to monitor the uptime of my site, first off when I go to my site sometimes it will instantly say error 521 web server is down, and I refresh once or twice and it works, it was never down. This happens even on the droplets direct ip. Second uptimerobot says it has a 77% uptime, and its still going down, the site goes out for about a hour at a time, randomly. I can even send just 4 GET requests to my server through an app, and the entire website wont load almost like its overloaded, but all the node logs have no errors. Im pretty sure this is just DO because I try the same exact code with a different host, and I have no downtime errors, and it doesnt crash when sending a few simple GET requests… anyone know why or how this is DO or how to fix it?