I come across an error 502 with a message notifying a server error:
The parameters of the query are as follow:
Could you please help?
I have just tried your request, and I get a result (with HTTP status 200 ok).
DSS HTTP status codes are documented on this page. A 502 is a server error, more precisely: "The server, while acting as a gateway or proxy, received an invalid response from the upstream server it accessed in attempting to fulfill the request."
If the 502 occurred during the weekend, that could have been a maintenance period, in which case that would be normal.
Can you try again and see if you get the same error ?