Hello Herve,
Thanks for reaching out to the Microsoft Q&A forum Support.
If I get you correctly, In Outlook, you have Gmail (IMAP), an Outlook account, and a Microsoft account. When adding an Outlook task tag in OneNote, nothing happens because the task owner defaults to your Gmail address. You want tasks to use your Outlook account instead.
Kindly go ahead to Set your Outlook account as default in Outlook
- Go to File > Account Settings > Account Settings.
- Under Email, select
****@outlook.frand click Set as Default. - Under Data Files, also set its data file as default.
- Restart Outlook and OneNote so the change applies.
- Verify in OneNote: Insert a task tag again; it should now create a task in your Outlook/To Do accountt Settings.
- Under Email, select
****@outlook.frand click Set as Default. - Under Data Files, also set its data file as default.
- Under Email, select