Servo only moves once

Question

I'm currently working on a school project that uses a servo to bring an arm into a position and then activate a pump with stepper motors. For this I use an STM32 Nucleo L152RE. The problem is that the servo moves to the first position but then the controller stops and the led ld2 starts blinking and then the controller no longer responds until I reset it. Everything has to be connected correctly because the servo works once.

#include "mbed.h"
#include <chrono>

PwmOut servo(PC_7);
InterruptIn s1_pos1(PA_10);
InterruptIn s2_pos2(PA_6);
InterruptIn s3_pos3(PA_1);

PortOut motor(PortC, 0xf00);

int m_state[4] = {0x300, 0x700, 0xc00, 0x900};

Timer timer;

unsigned int const T_periode = 20;

void moveServoToPosition(int position) {
    printf("Moving servo to position %d\r\n", position);
    switch (position) {
        case 1:
            servo.pulsewidth_us(500);
            break;
        case 2:
            servo.pulsewidth_us(1500);
            break;
        case 3:
            servo.pulsewidth_us(2500);
            break;
        default:
            break;
    }
}

void m_pump() {
    printf("Inside m_pump\r\n");
    if (std::chrono::duration_cast<std::chrono::milliseconds>(timer.elapsed_time()).count() < 15000) {
        for (int i = 0; i < 4; i++) {
            motor = m_state[i];
            ThisThread::sleep_for(4ms);
        }
    } else {
        for (int j = 0; j < 100; j++) {
            for (int i = 3; i >= 0; i--) {
                motor = m_state[i];
                ThisThread::sleep_for(4ms);
            }
        }
        motor = 0x000;
        timer.stop();
        timer.reset();
    }
}

void isr_s1_pos1() {
    printf("ISR s1_pos1 triggered\r\n");
    moveServoToPosition(1);
    m_pump();
}

void isr_s2_pos2() {
    printf("ISR s2_pos2 triggered\r\n");
    moveServoToPosition(2);
    m_pump();
}

void isr_s3_pos3() {
    printf("ISR s3_pos3 triggered\r\n");
    moveServoToPosition(3);
    m_pump();
}

int main() {
    s1_pos1.mode(PullDown);
    s1_pos1.rise(&isr_s1_pos1);

    s2_pos2.mode(PullDown);
    s2_pos2.rise(&isr_s2_pos2);

    s3_pos3.mode(PullDown);
    s3_pos3.rise(&isr_s3_pos3);

    servo.period_ms(T_periode);

    while (true) {
    }
}

I tried debugging the controller but couldn't get it to work.