The WSJ recipe will download around 70% of the first articles for an issue, but the remaining articles will get only the text "Too Many Requests". Could the explanation be that archive.is rate limits requests, for example allowing only so many requests per minute? (PR 2075 in release 6.29 notes the switch to archive.is:
https://github.com/kovidgoyal/calibre/pull/2075)
Assuming that rate limiting is the root cause, is there a way to configure the number of download threads or otherwise slow down Calibre downloads so that it can get all articles for each WSJ issue?