Hello trying to build a register page with no success (Network error), react native & mysql

im trying to build a register page, but on clicking the button 'Register' nothing happen, getting this error:

[12:54:39] Network Error
- node_modules\axios\lib\core\createError.js:15:17 in createError
- node_modules\axios\lib\adapters\xhr.js:81:22 in handleError
- node_modules\event-target-shim\dist\event-target-shim.js:818:20 in EventTarget.prototype.dispatchEvent
- node_modules\react-native\Libraries\Network\XMLHttpRequest.js:600:10 in setReadyState
- node_modules\react-native\Libraries\Network\XMLHttpRequest.js:395:6 in __didCompleteResponse
- node_modules\react-native\Libraries\vendor\emitter\EventEmitter.js:189:10 in emit
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:416:4 in __callFunction
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:109:6 in __guard$argument_0
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:364:10 in __guard
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:108:4 in callFunctionReturnFlushedQueue
* [native code]:null in callFunctionReturnFlushedQueue

I have seen similar problems like mine, but their solutions doesn't worked for me.

tried to change localhost to IP, tried to add to AndroidManifest.xml the rows:

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
    <uses-permission 
      android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>   

       ....
       android:usesCleartextTraffic="true"

but nothing helps, im pretty frustrated can't figure out my problem.

react code:

import React,{useEffect,useState} from "react";
import {View,TextInput,Text,StyleSheet,Button} from "react-native";


import axios from "axios";

const RegistrationScreen = () => {

    const [username,setUsername]=useState("");
    const [email,setEmail]=useState("");
    const [password,setPassword]=useState("");

    const [isSubmit,setIsSubmit]=useState(false);

    useEffect(()=> {
        const authenticate = async() => {
            axios.post(
                "http://10.0.0.8:8080/project/register.php",
                JSON.stringify({
                    email: email,
                    password: password,
                    username: username,
                })
            )
            .then((response) => {
                console.log(response);
                setIsSubmit(false);
            })
            .catch( (err) => {console.log(err);
            });
        };
        if (isSubmit) authenticate();

    },[isSubmit]);

    return (
        <View style={styles.container}>
            <TextInput 
                placeholder="Username" 
                style={styles.input} 
                autoCapitalize="none"
                onChangeText={(text)=>setUsername(text)}
            />
            <TextInput 
                placeholder="Password" 
                style={styles.input} 
                autoCapitalize="none"
                onChangeText={(text)=>setPassword(text)}
                secureTextEntry= {true}
            />
            <TextInput 
                placeholder="Email" 
                onChangeText={(text)=>setUsername(text)}
                style={styles.input}
            />
            <Text>{username}</Text>
            <View style={styles.buttonContainer}>
                <Button title="Register" onPress={() => setIsSubmit(true) }/>
            </View>
        </View>
    );
};

const styles=StyleSheet.create({
    container: {
        flex: 1,
        alignItems: "center",
        justifyContent: "center",
    },
    input: {
        paddingVertical: 5,
        borderBottomColor: "#ccc",
        borderBottomWidth: 1,
        width: "55%",

    },
    buttonContainer: {
        marginTop: 20,
    },
});


export default RegistrationScreen;

php code :

<?php 
    $conn = mysqli_connect('localhost', 'root', '','project_db');
    $json=file_get_contents('php://input'); // Takes raw data from the request
    echo $json;
    $obj=json_decode($json,true); // Converts it into a PHP object

    $username=$obj['username'];
    $password=$obj['password'];
    $email=$obj['email'];
    
    echo $username;
    echo "hello";

    $query="SELECT * from users where email = '{$email}'";
    $query_output=mysqli_query($conn,$query) or die ("Query faild: ".mysqli_error($conn));
    $count=mysqli_num_rows($query_output);

    if($count==1) {
        $arr=array("result"=>"email already present");
        echo json_encode($arr);
    } elseif($count==0) {
        $query1="INSERT INTO `users` (`email`,`password`,`username`) VALUES ('{$email}','{$password}','{$username}')";
        $query_output=mysqli_query($conn,$query1) or die ("Query faild: ".mysqli_error($conn));;
        $arr=array('result'=>'ok');
        echo json_encode($arr);
    } else {
        $arr=array('result'=>'fail');
        echo json_encode($arr);
    }

?>

help someone please ?