ForbiddenException: WebDavBackend against Nextcloud when creating new file

[grote]

Seems to be a transient error as subsequent attempts (maybe with a different file) succeeded:

10-21 09:12:53.688 31346 31355 I KVBackup: Finish K/V Backup of @pm@
10-21 09:12:53.710 31346 31355 D MemoryLogger: 48 MiB free - 27 of 75 (max 256)
10-21 09:12:56.860 31346 31355 D o.c.s.c.b.w.WebDavBackend: [binder:31346_1      ] https://example.org/remote.php/webdav/.SeedVaultAndroidBackup/782c3023961762fdcea050f6f0bfb7438d4d9998248617c48b13560c0cada7f4/4b not found, creating...
10-21 09:12:57.987 31346 31355 W o.c.s.c.b.w.WebDavHelper: [binder:31346_1      ] Error creating https://example.org/remote.php/webdav/.SeedVaultAndroidBackup/782c3023961762fdcea050f6f0bfb7438d4d9998248617c48b13560c0cada7f4/4b: at.bitfire.dav4jvm.exception.ConflictException: HTTP 409 Conflict
10-21 09:12:59.200 31346 31355 E BackupCoordinator: Error finishing K/V backup for @pm@
10-21 09:12:59.200 31346 31355 E BackupCoordinator: at.bitfire.dav4jvm.exception.ForbiddenException: HTTP 403 Forbidden
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at at.bitfire.dav4jvm.DavResource.checkStatus(DavResource.kt:640)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at at.bitfire.dav4jvm.DavResource.checkStatus(DavResource.kt:624)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at at.bitfire.dav4jvm.DavResource.mkCol(DavResource.kt:271)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at at.bitfire.dav4jvm.DavResource.mkCol$default(DavResource.kt:257)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at org.calyxos.seedvault.core.backends.webdav.WebDavHelperKt.mkColCreateMissing(WebDavHelper.kt:67)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at org.calyxos.seedvault.core.backends.webdav.WebDavHelperKt.mkColCreateMissing(WebDavHelper.kt:76)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at org.calyxos.seedvault.core.backends.webdav.WebDavHelperKt.ensureFoldersExist(WebDavHelper.kt:98)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at org.calyxos.seedvault.core.backends.webdav.WebDavBackend.save(WebDavBackend.kt:127)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at com.stevesoltys.seedvault.repo.BlobCreator.createNewBlob(BlobCreator.kt:72)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at com.stevesoltys.seedvault.repo.BackupReceiver.onNewChunk(BackupReceiver.kt:119)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at com.stevesoltys.seedvault.repo.BackupReceiver.finalize(BackupReceiver.kt:104)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at com.stevesoltys.seedvault.repo.BackupReceiver.readFromStream(BackupReceiver.kt:87)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at com.stevesoltys.seedvault.transport.backup.KVBackup.finishBackup(KVBackup.kt:165)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at com.stevesoltys.seedvault.transport.backup.BackupCoordinator.finishBackup(BackupCoordinator.kt:322)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at com.stevesoltys.seedvault.transport.ConfigurableBackupTransport$finishBackup$1.invokeSuspend(ConfigurableBackupTransport.kt:139)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:108)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:280)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:85)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:59)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source:1)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:38)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source:1)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at com.stevesoltys.seedvault.transport.ConfigurableBackupTransport.finishBackup(ConfigurableBackupTransport.kt:138)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at android.app.backup.BackupTransport$TransportImpl.finishBackup(BackupTransport.java:790)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at com.android.internal.backup.IBackupTransport$Stub.onTransact(IBackupTransport.java:682)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at android.os.Binder.execTransactInternal(Binder.java:1505)
10-21 09:12:59.200 31346 31355 E BackupCoordinator: 	at android.os.Binder.execTransact(Binder.java:1444)
10-21 09:12:59.213 31346 31355 I NotificationBackupObserver: Completed. Target: @pm@, status: -1002
10-21 09:12:59.213 31346 31355 I NotificationBackupObserver: Showing progress notification for se.lublin.mumla 113/346
10-21 09:12:59.213  1714 31418 E KeyValueBackupTask: Error during PM metadata backup
10-21 09:12:59.213  1714 31418 E KeyValueBackupTask: com.android.server.backup.keyvalue.AgentException
10-21 09:12:59.213  1714 31418 E KeyValueBackupTask: 	at com.android.server.backup.keyvalue.KeyValueBackupTask.handleTransportStatus(KeyValueBackupTask.java:1131)
10-21 09:12:59.213  1714 31418 E KeyValueBackupTask: 	at com.android.server.backup.keyvalue.KeyValueBackupTask.sendDataToTransport(KeyValueBackupTask.java:1074)
10-21 09:12:59.213  1714 31418 E KeyValueBackupTask: 	at com.android.server.backup.keyvalue.KeyValueBackupTask.sendDataToTransport(KeyValueBackupTask.java:578)
10-21 09:12:59.213  1714 31418 E KeyValueBackupTask: 	at com.android.server.backup.keyvalue.KeyValueBackupTask.backupPm(KeyValueBackupTask.java:683)
10-21 09:12:59.213  1714 31418 E KeyValueBackupTask: 	at com.android.server.backup.keyvalue.KeyValueBackupTask.run(KeyValueBackupTask.java:369)
10-21 09:12:59.213  1714 31418 E KeyValueBackupTask: 	at java.lang.Thread.run(Thread.java:1012)
10-21 09:12:59.213 31346 31355 I NotificationBackupObserver: 113/346 - System package manager (@pm@)
10-21 09:12:59.234  1714 31418 V BackupManagerService: [UserID:0] Ancestral packages:  243
10-21 09:12:59.412 31346 31355 I BackupCoordinator: Request incremental backup time. Returned 0
10-21 09:12:59.418  1714 31418 I KeyValueBackupTask: K/V backup pass finished
10-21 09:12:59.430 31346 31357 I NotificationBackupObserver: Backup finished 113/346. Status: -1000
10-21 09:12:59.430 31346 31346 D ConfigurableBackupTransportService: Service destroyed.