I don't think these internal errors have any corresponding specific error codes similar to HTTP codes. I believe this message is surfaced when it's not a specific error caught in Shopify. A lot of the time I've seen it has been timeouts. For the most part I would suggest just retrying when you hit these errors, and if it's consistently happening include the query, shop, and a timeframe for further investigation.
Thanks Ryan. I didn't try to do a try and repeat the operation right after, I didn't think of a timeout. I didn't think about it because pressing the "submit" button even after a minute, the operation is not successful. The only solution in this case is: reload the page and do it all over again (losing the sequence of changes made by the user). It's very annoying. Very annoying even not knowing what the mistake corresponds to. Normally during an exception the runtime environment reveals the error message to the programmer. I get a code here that I know nothing about, except Shopify. It is the first time that I have to ask the service provider (and I pay) for the explanation of the error. I am increasingly disoriented and disheartened. If I had created an e-commerce from scratch, I would have finished 4 months. I try again to ask: is there a synoptic table of GraphQL errors?
Thanks for your reply, Ryan.