Are you using ArcGIS Enterprise or ArcGIS Online? If it's the former, please check (or ask your admin to check) whether the ArcGIS Data Store is full and is in read-only mode.
If the data is registered to an enterprise geodatabase, ensure that the RDBMS server is not full as well.
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was this by any chance on Monday morning?
some of AGOL's data servers were "down" for the first few hours of the morning on Monday.
their status page says it was up and running, but it was not. I could view Item details on my hosted layers, but, no data tab/data, and error messages saying it couldn't find something, and nothing was working correctly.
an hour or so later, it was back up.
Have you tried again just to see if it was during the undocumented outage?