When an upstream calendar no longer exists, HTTP 422 is shown instead of a useful message

[ivystopia]

May be specific to Proton Calendar URLs.

After deleting a calendar in Proton Calendar, icsx obviously cannot sync it any more.

But the error is quite technical and doesn't mention which calendar is causing the problem.

HTTP 422 

java.io.IOException: HTTP 422 
	at at.bitfire.icsdroid.CalendarFetcher.fetchNetwork$icsx5_92_2_4_3_standardRelease(SourceFile:181)
	at at.bitfire.icsdroid.CalendarFetcher$fetchNetwork$1.invokeSuspend(Unknown Source:11)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:34)
	at kotlinx.coroutines.DispatchedTask.run(SourceFile:100)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(SourceFile:586)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(SourceFile:829)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(SourceFile:717)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(SourceFile:704)

[ArnyminerZ]

I wonder why Proton answers with 422, it should be responding with 404. I don't know how we can know that 422 is an error for a calendar that no longer exists...