Teamviewer always off

[TeaForTwo]

Hi everyone,

I setup teamviewer on couple computers, I could remote unattended connect them before, there was no problem.
now, I always get disconnect from those computers. Teamviewer shows those computers offline, but I'm 100% sure computer is online.

When I use another way to login computer, then I saw Teamviewer said xxx computer is online.
When I log off computer, Teamviewer shows computer offline, then I could not to remote unattendedly control those computer.
I'm 100% sure the disable Teamview shutdown.

Thanks for any help.
TeaForTwo