Teamviewer access with Windows10 on remote pc

Using a mac to try and access a remote pc running W10. It finds the pc. The icon is black and the message says remote pc is, "teamviewer is not running on partner computer". The software is up to date on both compuerts and they are both switched on. I tried switching off the firewall. It made no difference. Can anyone help? Is there a setting in Win10 to allow access?