what to do when i can't access my old OneNote notes?

(Please note that this is Brazilian Q&A Forum, any threads should be posted in Portuguese. However, I will still provide an answer in English based on your initial response.)  

Hi, RubeTaria ㅤ

This sounds more like a sync/account issue than the notes being gone, especially since the note colors updated but the contents did not. That usually means OneNote is seeing part of the cloud notebook, but the phone app is not loading the full synced content correctly.

Here are some suggestions you can try:

First, check that you are signed into the exact same Microsoft account you used on the old phone. If you have more than one account, personal, school, or work, add the other account in OneNote too, because notebooks may be attached to a different login.

Next, open OneNote on the web from a browser and sign in there. If the notes appear online, the notes are still safe, and the issue is likely with the phone app’s sync. I recommend using the web version to check whether the problem is with OneNote on the device or the cloud notebook.

On the phone, go to OneNote’s notebook list, open the menu, then use Settings > Sync all, or sync the affected notebook manually. Keep the app open while it syncs. On Android, it is also recommended that you sign out and sign back in to reset the account connection.

Also check Deleted Notes, Misplaced Sections, and your OneDrive recycle bin. These are listed as possible recovery places for missing or unsynced notes.

I would avoid uninstalling again for now, especially if anything might still be unsynced locally. It is recommended that you confirm the notes are visible in OneNote web or another device before doing more resets.

Thank you for your patience in reading, I hope this information has been helpful to you. 

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