communication problem between 2 ble ,one on uno one on mega

Hi
I have a problem I'm straggling to fix for more than a weak whiteout success
I have one ble link on the uno threw joystick shield v2, defined as master, and sending data threw the serial.print command ,three numbers at a time with an 's' character at the end
I have a second ble , on a mega board threw expansion shield. The mega reads data from serial communication, by serial.read. The ble defined as peripheral, and have default definitions.
These is a connection established between the two of them , as the green indicator is on both sides.
these is an example of the reading code on the mega:
if (Serial.available())
{
char c[10];
for (int i=0; i<10;i++)
{
c[i] = 0;
}
c[0] = Serial.read();
int i =0;
while (c[i]!='s' && i<10)
{
i++;
c[i] = Serial.read();
}
Serial.print(c);
Serial.print(" ");
Serial.println(counter_time);
}

The problem: The mega board is not getting any information from the serial.read, the check Serial.available()) is not true.
When I connect the ble directly to the pc threw usb cable, I can I see in the serial monitor of the ble port, the data coming in. So my problem is somewhere between the mega board and ble link.

I tried switching to different expansion board, didn’t work, and to different mega board, didn’t work either. Don’t know what to do anymore