Cannot connect to Digi One SP

I’ve got a 2003 Server which connect to many DIGI SP One with RAS.
After a night, we connect the DIGI with the RAS but we cannot open the port.
If i check the option “Always Grant port open request”, the port is opened but i do not receive any data.
I must initialize the port 3 times to receive data.

How can I resolve this problem ?