Hi Sergio,
Do you mean Folder Pane is invisible or certain folders are missing?
Do all folders show correctly on the web mail?
If you mean the whole Folder structure, please make sure folder pane
is turned on. Please click View > Sidebar to enable it and then check the result.
Normally, we can right click your mailbox and choose “Synchronize Now” to force the update.

If that doesn’t work, please remove and then re-add your Exchange account to see if all folders will be synced.
Any updates, please feel free to post back.
Regards,
Perry
Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact
tnsf@microsoft.com.

Click
here to learn more. Visit the dedicated
forum to share, explore and talk to experts about Microsoft Teams.