Hi, I face a pb with synchr Odoo/outlook calendar

- It has worked for all the users. A point, migration V12 to V14 on 21/nov
- Now, it works for some users...
I noticed that for users KO the Microsoft Next Sync Token is not generated after clic button synchronized calendars
I've read forum's posts about approval of email adresses and microsoft tenants--> first check
Can someone help for checklists / process to do (except odoo doc, I read it several time)?