Within the Teamwork Chrome extension, you can disconnect your linked Teamwork site.
If you are experiencing problems creating items via the extension, try disconnecting and adding your site again.
You can do this by clicking the Teamwork extension icon in your tool bar and then select the settings cog icon.
In the Settings & Accounts view, you will see all of the sites you are currently connected to listed here.
Hovering over an account will show an X that you can click to disconnect it.
For more information, see: Installing Teamwork for Chrome