Also a possibility that it's not related to the authoritative servers for the domain directly, but a misconfiguration on a higher-level. We've seen everything from a TLD that specifically blocked Let's Encrypt's traffic to their DNS server, to a TLD that set a CAA record, to a TLD that didn't support TCP. But, most commonly these intermittent issues are from something like inconsistent delegations where some of the servers are not answering authoritatively, and so if one of those servers gets picked then it won't work (or might time out before retrying enough times to find a server that does work).
But yeah, your options are either troubleshooting it yourself, or having other people help you troubleshoot it. Or not bothering and just hoping it continues to occasionally work by accident.