iOS build failing: "Error while gathering & validating credentials", "Request failed with status code 404"

Expo SDK
2

Adding more debug logging, we see this as the failing URL (same as “nfen” saw in exp build:ios Error while gathering & validating credentials (status code 404) - #7 by nfen):

{ hostname: 'exp.host',
  port: null,
  path: '/--/api/updateCredentials/%5B%5D',
  method: 'post',
  headers:
   { Accept: 'application/json, text/plain, */*',
     'Content-Type': 'application/json;charset=utf-8',
     'Exp-ClientId': 'c--kniJmVRQyitCtNZoDg8aw',
     'Expo-Session':
      '{"id":"c7e31cb8-b202-4c39-b607-a5c4255f215d","version":1,"expires_at":1893456000000}',
     'User-Agent': 'axios/0.16.2',
     'Content-Length': 17130 },
  agent: undefined,
  auth: undefined }