Calendar module fails to fetch data and discards old data, leaving nothing

[fribse]

So I see this every morning:

0|MagicMirror  | [13.02.2022 12:34.28.850] [ERROR]
0|MagicMirror  | Calendar Error. Could not fetch calendar:  http://p01-calendarws.icloud.com/ca/subscribe/1/IsLh6fUURb4n_nA6vhWYUmlEe98rz2BN8BhioUPzrC2HVohwJIUCbGuGeTwczZWvXjTqU7vicBATXHojb1p5fn8ub3RCBUwKfHm3jXJDzFE Error: Service Unavailable
0|MagicMirror  |     at NodeHelper.checkFetchStatus (/home/pi/MagicMirror/js/node_helper.js:121:9)
0|MagicMirror  |     at processTicksAndRejections (node:internal/process/task_queues:96:5)

Which gives this result in the mirror:

Later in the day, the calendar days are fetched, and then updated on the screen.
Why does the module discard the existing days when it can’t get the new download?
My guess is that the calendar is somehow throttled, and thus rejects requests when there are too many, so how do I make the calendar module keep the old data until it can get new data?

[sdetweil]

@fribse the module design is all or nothing.

when it gets an error, theat is reported and the displayer has nothing.

you would have to change the code