Can't sync Android Notes app to Nextcloud

Nextcloud version (eg, 12.0.2): 17.0.3
Operating system and version (eg, Ubuntu 17.04): Ubuntu 18.04.4

The issue you are facing:

Yesterday my Notes app stopped syncing with Nextcloud.

Can anyone help troubleshoot this?

Here’s what happens when I try to get the Android Notes app to sync with my NC instance:

App Version: 2.10.3
App Version Code: 81
Files App Version Code: 30100190


OS Version: 4.14.111-gb7713fd5d6ed-ab5820689(5831595)
OS API Level: 29
Device: flame
Model (and Product): Pixel 4 (flame)

--- Provided authentication token does not match or package name is not permitted to perform this action
	at it.niedermann.owncloud.notes.persistence.NotesClient.requestServer(
	at it.niedermann.owncloud.notes.persistence.NotesClient.getNotes(
	at it.niedermann.owncloud.notes.persistence.NoteServerSyncHelper$SyncTask.pullRemoteChanges(
	at it.niedermann.owncloud.notes.persistence.NoteServerSyncHelper$SyncTask.doInBackground(
	at it.niedermann.owncloud.notes.persistence.NoteServerSyncHelper$SyncTask.doInBackground(
	at android.os.AsyncTask$
	at android.os.AsyncTask$SerialExecutor$
	at java.util.concurrent.ThreadPoolExecutor.runWorker(
	at java.util.concurrent.ThreadPoolExecutor$


You need to clear the Notes app storage (at least it worked for me). Beware, unsync’ed notes will be lost.