Looking for advice on the recurring 504 Gateway Timeout when fetching preview lists for our Chicago outbound campaigns via GET /api/v2/outbound/contactlists/{contactListId}/contacts.
“The contact list API supports pagination with a maximum limit of 1000 records per request.”
Our lists are well under that limit, yet the request hangs for 60 seconds before failing. Is this a known latency issue with large contact segments in the US-East region?