My first guess is it's a timeout due to how many games/matches the player has.
Error in player matches archive

This is part of my script for checking matches for different teams in the same league competition, not an ad hoc call. I have submitted a bug report but no idea how the new system of reporting will deal with it. We used to get a reponse from support. Sadly no more.

Works on my laptop though...
The problem is with that specific member, not in general.

This is part of my script for checking matches for different teams in the same league competition, not an ad hoc call. I have submitted a bug report but no idea how the new system of reporting will deal with it. We used to get a reponse from support. Sadly no more.
If it's due to the number of matches, then it's not a bug exactly but a limit due to the time it takes because of the record size. Same as the club endpoint for very large clubs.
Staff have your bug report but when submitting a bug report through the tool you won't normally get any response unless staff need more information.

After three consecutive days of same error on this end point it has been resolved.
No idea if it self corrected or if devs corrected. No feedback.

After 11 days I have a reply from 'Support'. They tell me it's OK now.
No information about why or how it was resolved.
2 day turn round for support is a complete falicy.

After 11 days I have a reply from 'Support'. They tell me it's OK now.
No information about why or how it was resolved.
2 day turn round for support is a complete falicy.
2-3 days is the average. There's always going to he outliers on both sides of that time frame. 11 is a lot but there were done recent changes, on top of the new system, that likely increased time to response on some tickets

It's also unlikely anything specific was done and the normal cache invalidation process resolved the issue.

Thank you martin. I agree that is likely. However the 11 day response (Oh we are so busy) is nonsense in the light of the statements about 2 day support turnround. And what I got back was a complete waste of time. It provided no useful information at all. I had already posted here, 10 days ago that it had been corrected.

And an average of 2-3 days also means that some get dealt with in less time. I have reported many bugs over the last couple of years (there have been a few) and NEVER recieved a response within three days. Generally 5 day+. (Still waiting for an answer for some)

I guess you get fast answers for questions of low importance or complexity, like "oh no I don't know how change my profile picture" or "how do you do pre-moves", pointing to already existing help topics. Or maybe the count the bot answer in all that, dropping the average value. Who knows.

And an average of 2-3 days also means that some get dealt with in less time. I have reported many bugs over the last couple of years (there have been a few) and NEVER recieved a response within three days. Generally 5 day+. (Still waiting for an answer for some)
Bug reports almost never get any kind of response unless more information is needed. Only tickets directly to support get a response.

And working again. Got a message fron support that devs couldn't replicate the problem. I suspect that implies it is self correcting due to a DB refresh and could well come back due to the size of the archive.
Also 3 day turn round for response. Not bad. Best I've had I think.

And error back again. As we have now been told that API users have no priority and this is likely to be corrected by some internal DB automatic process at some point, I doubt it's worth a bug report.
No prospect of any long term solution here. And as archives get larger more players will doubtless become a problem.
Can't access player match archive
https://api.chess.com/pub/player/xhantian/matches