CoinpaymentsAPI

PHP Code:

use App\Libraries\coinpayments\src\CoinpaymentsAPI; 


This means that the class not only needs to be in this path, but also has a corresponding namespace.

It looks like you are using an official API wrapper.
You need to use loading via classmap.

PHP Code:

    public $classmap = [
        'CoinpaymentsAPI' => APPPATH . 'Libraries/coinpayments/src/CoinpaymentsAPI.php',
    ]; 


PHP Code:

use  CoinpaymentsAPI;
....
new CoinpaymentsAPI(...); 


question to upload to localhost works without problem but when uploading from a server it throws an error Class 'CoinpaymentsAPN' not found


public $classmap = [
        'CoinpaymentsAPN' => APPPATH .'Libraries\coinpayments\src\CoinpaymentsAPI.php'
    ];


<?php

namespace App\Controllers;
use App\Controllers\BaseController;
use CoinpaymentsAPN;

Error
Class 'Coinpaymentsapn' not found
APPPATH/Controllers/Dashboard.php at line 300

Code:

300                         $cps_api = new Coinpaymentsapn($private_key, $public_key, 'json');