To uninstall and deprovision the new Teams for all users, use the following PowerShell command:

Download teamsbootstrapper.exe from Microsoft.

./teamsbootstrapper -x

Original link

To install new Teams on a single computer with many users, follow these steps:

1. Download the .exe installer. If you have downloaded this file previously confirm you have the latest version by comparing the properties on each file.
2. Open the Command Prompt as an Admin.
3. At the prompt enter: .\teamsbootstrapper.exe -p
4. A success or fail status displays.
   

Here is the original link from Microsoft.

Please try the following:

Fully exit out any Office 365 APPs first.

1.  Log off word account and log back in
2.  Remove all the office 365 apps credentials in Windows Credentials

If all failed, please try:

close all office apps

Go to the AAD identity folder in :  C:\Users<Username>\AppData\Local\Packages\Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy\Settings

Rename Settings.dat to settings.datold

Go to  C:\Users<Username>\AppData\Local\Packages\Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy\AC\TokenBroker\

Rename folder Accounts to accounts-old