Progress AppSever can't access remote directory

Greetings.

appserver 11.7 win.

I created the procedure that is remotelly run :

DEFINE INPUT  PARAMETER pContent AS CHARACTER NO-UNDO.

OUTPUT TO \\server4\txt-ati\test.txt.
PUT UNFORMATTED pContent SKIP.
OUTPUT CLOSE.

CATCH myS AS Progress.Lang.SysError :    
    RETURN ERROR NEW Progress.Lang.AppError(myS:getmessage(imgs1), 404).
END CATCH.

 And it complains about:

Impossible to open file:\\server4\txt-ati\test.txt errno=13. (98).

The shared folder on \\server4  (windows 7) has granted access to everyone as R/W.

From  cmd window on the appserver, I can :   copy con \\server4\txt-ati\test.txt and it is executed correctly.

but the appserver process can´t do that.  I have disabled firewall on server4.

The directory is in use by a third party appserver, that takes that data (test.txt) and is injected in another software that aggregates data.

Even with that appserver shutdown, appserver can´t create the file over the network.

Am I missing something?