Teams Version 1.0.00.26863 updated 2/15/18. It is 64 bit edition (apparently I can't include the numbers 63 and 64 with a space between them in this community???)
On another computer I have added a previously used Onenote notebook to a team so that we can use our pre-existing onenotes in Teams. This is working fine on my office computer.
Tried my home computer in Teams this morning and got the message "Failed to execute getToken from teams:Tab does not have the required permissions for this operation" when trying to access the Notebook. This happens on more than one Notebook but not on all of them.
I do have the Onenote open on my computer which verifies that my permissions in Onenote itself is fine.