If you're needing to download any of the National Archives of Ireland's Calendars of grants of probate of wills and letters of administration from 1858 to 1982 (held in CS/HC/PO/4), you're out of luck. This won't be a surprise to some researchers. The online links to download pdf copies of the annual calendars, previously available via the the online catalogue, are out of action.
I don't know how long this has been the case. While an NAI member of staff told me this problem has been ongoing for 'a while', he wasn't able to confirm how long 'a while' meant. However, he was able to tell me that the technical team is aware of the problem and will fix it as soon as is possible.
Up to 1917, the calendars in this collection cover the whole of the island of Ireland. From 1918 onwards they cover only the 26 historical counties in the Republic. Those indexes covering the six counties of Northern Ireland since 1918 are in the Public Record Office of Northern Ireland (PRONI) and are not affected by this NAI techie issue. You can search and view here.
UPDATE, 26 APRIL 2024: A message advising the above had been placed on the home page of the NAI and a parallel tweet says that researchers can email query@nationalarchives.ie for any calendars they may need.