Office 365 - "Due to organizational policies, you can't access these resources" error

I think you have to remove the IP restrictions from SharePoint Online device access policy.
https://danmyhre.wordpress.com/2017/06/22/microsoft-teams-sharepoint-online-integration-not-working/

Useful link:
https://thesharepointfarm.com/2015/08/sharepoint-2016-adds-ip-access-restrictions/

Thank you for such a fast response.  I've checked the Device Access, Control access by network location . . . in the SharePoint admin portal, and there are no restrictive entries.  It appear that only one user in our office is having this error message.

The user logged onto another computer on our office domain and O365 worked perfectly.  Is there a setting on her client computer that we could check?

Hi,

We have the same problem with 2 of our users (team of about 50).
Started 2 days ago.

All settings appear to be correct :s

Edit:
If I click OK in Office, it gives me the change to login (again)
Then I get the error "AADSTS165000: Invalid Request: The request tokens do not match the user context.... Reasons:[Token is invalid]"

We called MS Support and had Help login to the affected computer.  The tech lady elevated some settings in the Exchange online console, deleted some credentials on the local machine in Control Panel, Credential Manager, and even performed a soft re-install of the O365 software through Control Panel, Programs, but with no luck.

We tried another domain user's computer here in the office, with the affected user logging into O365 with her password.  Everything worked properly, with her files opening properly in Excel on the local machine.

The tech concluded that the user profile is corrupted on only the local machine of the affected O365 user.  The tech recommended we delete that profile and recreate it.

Thank you all for your help!

Thanks

Had nothing todo with permissions at our site
We solved it by:

-  Logging out of everything (office, office online)
- Clearing cashes of internet explorer (most importantly cookies)
- Delete all credentials that had to do with Microsoft from the credential store (even the exchange settings, everything with MSO or something like that deleted)
- Rebooted
- Logged in to SharePoint Online in IE -> checked "remember me"
- Started an office application and logged in (not sure if it asked actually :s)
- Opened a office document from SharePoint on pc logged in again -> fail
- entered credentials again and waited a minute or so
-> success

Did almost the same the day before, except the reboot and I also didn't clear the credential store  that well.

What are credentials?  Where do I access them?

Thank you for that useful information, Jeroen Heymans.  I solved my problem by creating a fresh user account in Windows (and deleting the origninal one).  My solution probably accomplished the same things that you did manually.