BLE read from arduino unsucessful

I can write data to firebeetle 328p using BLE but I can't read it.

The BLE characteristic that reads and writes on the arduino has all the following attributes: "Read" "Write" "Notify" "WriteWithoutResponse".

So I have:

b=ble("MACADDRESS");
c = characteristic(b,"DFB0","DFB1");
write(c,"send");
write(c,"stop");

and the arduino starts sending data or stop sending data when I run "send" or "stop". I can see the tx and rx leds in the arduino working.

But when I try to subscribe to recieve data:

subscribe(c,"notification")

I get the following error:

"Operation failed because write is not permitted."

But, as I mentioned before the BLE characteristic has a write attribute, and I can acctualy write on it (as mentioned before). But the subscribe function gives me the error that write is not permited

When I try to read with:

read(c)

I always get a value of 1, which does not correspond to the value that arduino is sending.

Does anyone has an idea if there is a bug with the subscribe function or anyone has a suggestion to solve this problem?