No connection to TeamViewer server on Win2012R2

hi
I've just install a customized TV12 host on a Win2012R2 server:
- with the run as administrator option
- and with an account local administratror
.
I adjust the TV12 setting :
- never change password
- setting the password
- log on only by administrator
- .....

1st strange state
I restart the server and i'm unable to connect.
When i click on my TV shorcut, I've a message "TV12 is not running of the distant machine".

2st strange state
With another acces, I connect to the server via mstsc
When the session is opened, TV12 is started and I can connect with my TV.
I close the mstsc session, no disconect or other action, just close the mstsc windows.
The server is still viewable like connected but unable to connect : only the message conection in progress.

Have you an idea please ?

Vincent