WebGL context lost!

in Exporting
I recently exported a game in HTML zip file format to itch.io. Thing is, after I got it all set up and previewed it, it worked just fine the first time. But when I reloaded the page and tried playing it again I keep getting "WebGL context lost, try reloading the page" (in Chrome browser) or on Firefox I get "Indirect call to null. " Now I did set up a system for the game to save the player's high score on their device via singleton. Could that be causing my problem? Because I wasn't sure if running an HTML version in a browser would let me do that. That's just a theory I have, but could it be something else? But the fact that it worked the first time and then never again after is what has me scratching my head!
Answers
Hey, it is important that you use GLES2 not GLES3 else, it will not work.