Eli5: Why do some video players (Youtube, Netflix etc.) have problems with loading a video, only for it to be solved on a reload of the website?
Some parts of the process are deterministic: like when you press Enter / click/tap a button, that triggers the browser to start (re)loading the page. But others are non deterministic, like which exact path the emergent packets will take over the (inter)network. Reloading effectively dice rolls the non deterministic parts.
There are a few ways this could happen. A common one is timeouts. If you request something from a website and it starts taking too long, a lot of websites will just cancel it so the server doesn’t get overwhelmed. The timeout might be something like 10 seconds, and sometimes, when the server is busy, maybe it’s taking anywhere from 9-11 seconds to retrieve your data, so you might just get lucky or unlucky.
There are also errors that are transient. The programmers should fix these, but they’re so rare, that they may be difficult to track down and fix. Like, maybe the request fails because you tried to get it the exact millisecond something else happened.
Generally, video delivery sites like YouTube are served to users through a CDN (content delivery network) that has a bunch of nodes in a lot of different locations, this allows the site to be performant regardless of where you are loading it.
Reloading a site that isn’t loading is usually the result or one of these nodes not performing correctly. Reloading will connect you to a node that’s performing better.