A quick google search and I found a topic with the same problem. Hope it’s helpful - How to fix this data store error?. It might also be Roblox’s problem.
HTTP 502 is Bad Gateway, it essentially means that the host is down on Roblox’s end.
Here’s a little shortcut for determining what most HTTP error codes mean:
1XX - Informational (I don’t quite understand what these codes are but some of the status codes I know are related to switching to a websocket protocol for example)
2XX - Working as intended, nothing went wrong, and the request was accepted
3XX - Use a different location for this request (e.g. a redirect, the cache, etc)
4XX - Something inputted in the request is wrong or isn’t allowed
5XX - Something is wrong or went wrong on the server-side
Additionally, check out this resource for the standard meaning for HTTP status codes: iana.org HTTP status code registry
Some sites might misuse status codes or misrepresent them, but, generally you can expect all websites follow the standard unless its like someone’s hobby project.
Most likely no, Roblox has been facing some odd outages the past two or so days so I suspect that has to do with your DataStore issue.
Where is the error you’re getting coming from? Is it in game, or, in studio? Based on the full error message, it sounds like it could also be an https certificate issue (from the SSL stuff), not an HTTP 502 in which case the 502 number might mean something different. Are you able to access https://gamepersistence.roblox.com/ in your browser? If you get an OK message it means you’re able to connect just fine to it on your end and there’s no SSL/https issue for you, in which case if its only happening in studio it might be studio specific.