AES256 cannot decrypt previous encryption data after restarting server in java

Currently I'm having a problem that I don't know how to solve. It's the decryption and encryption of the string using AES256. Everything was working fine until I restarted the server and I couldn't decode the previous data. Hope everyone can help me. Thank you very much.

private static final String SECRET_KEY = "my_key";
private static final byte[] SALT;
private static final SecureRandom random;
private static final IvParameterSpec ivspec;

static {
    random = new SecureRandom();
    SALT = new byte[16];
    random.nextBytes(SALT);
    byte[] bytesIV = new byte[16];
    random.nextBytes(bytesIV);
    ivspec = new IvParameterSpec(bytesIV);
}

public static String encrypt(String stringToEncrypt) {
    try {
        SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
        KeySpec spec = new PBEKeySpec(SECRET_KEY.toCharArray(), SALT, 65536, 256);
        SecretKey tmp = factory.generateSecret(spec);
        SecretKeySpec secretKey = new SecretKeySpec(tmp.getEncoded(), "AES");

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivspec);
        return Base64.getEncoder().encodeToString(cipher.doFinal(strToEncrypt.getBytes(StandardCharsets.UTF_8)));
    } catch (Exception e) {
        System.out.println("Error while encrypting: " + e);
    }
    return null;
}

public static String decrypt(String stringToDecrypt) {
    try {
        SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
        KeySpec spec = new PBEKeySpec(SECRET_KEY.toCharArray(), SALT, 65536, 256);
        SecretKey tmp = factory.generateSecret(spec);
        SecretKeySpec secretKey = new SecretKeySpec(tmp.getEncoded(), "AES");

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
        cipher.init(Cipher.DECRYPT_MODE, secretKey, ivspec);
        return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt)));
    } catch (Exception e) {
        System.out.println("Error while decrypting: " + e);
    }
    return null;
}