AttachIntrerrupt stops NRF24L01+ from working - ARDUINO - arduino

Question

If I remove attachInterrupt(digitalPinToInterrupt(encoder1),readEncoder,RISING); The code works. But once its added, the radio.available doesnt let anything under it run.
#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>
RF24 radio(7, 8); // CE, CSN
const byte address[6] = "00001";
struct InputData // define stuct
{
int x;
int y;
};
InputData data;
// Motor A connections
int motor_enA = 9;
int motor_in1 = 10;
int motor_in2 = 6;
int encoder1 = 2;
int encoder2 = 3;
int counter = 0;
int angle = 0;
void setup() {
Serial.begin(9600);
radio.begin();
radio.openReadingPipe(1, address);
radio.setPALevel(RF24_PA_MIN);
radio.startListening();
// Set all the motor control pins to outputs
pinMode(motor_enA, OUTPUT);
pinMode(motor_in1, OUTPUT);
pinMode(motor_in2, OUTPUT);
// Turn off motors - Initial state
digitalWrite(motor_in1, LOW);
digitalWrite(motor_in2, LOW);
analogWrite(motor_enA, 255);
pinMode (encoder1, INPUT);
pinMode (encoder2, INPUT);
attachInterrupt(digitalPinToInterrupt(encoder1),readEncoder,RISING);
}
void loop() {
readEncoder();
if (radio.available()) {
radio.read(&data, sizeof(data));
// Serial.println(data.y);
if (data.y > 5) {
digitalWrite(motor_in1, HIGH);
digitalWrite(motor_in2, LOW);
}
else if (data.y < -5) {
digitalWrite(motor_in1, LOW);
digitalWrite(motor_in2, HIGH);
}
else {
digitalWrite(motor_in1, LOW);
digitalWrite(motor_in2, LOW);
}
}
if(counter>1){
counter=0;
angle+=2;
}else if(counter<-1){
counter=0;
angle-=2;
}
Serial.print("Position: ");
Serial.println(angle);
}
void readEncoder()
{
if(digitalRead(encoder1)==HIGH){
int b = digitalRead(encoder2);
if(b>0){
counter++;
}
else{
counter--;
}
}
}
I have tried removing and adding the line, as described above^^

Answer 1

as mentioned by Hcheung, make counter volatile and remove readEncoder(); from loop.
I simplify a bit ISR readEncoder();
volatile int counter = 0;
[....]
void readEncoder() {
//if(digitalRead(encoder1)==HIGH){ //we are precisely here because digitalRead(encoder1) = HIGH !
if(digitalRead(encoder2)) counter++;
else counter--;
}