Cannot connect remote database

I want get some data from aonther database, so i create a user [promission only have  "SELECT"], I check connect with terminal, it's good.
but in the codeigniter-4 . the logs is :
```
ERROR - 2023-10-10 11:26:03 --> Error connecting to the database: mysqli_sql_exception: Connection refused in /www/wwwroot/example.com/vendor/codeigniter4/framework/system/Database/MySQLi/Connection.php:185
Stack trace:
#0 /www/wwwroot/example.com/vendor/codeigniter4/framework/system/Database/MySQLi/Connection.php(185): mysqli->real_connect()
#1 /www/wwwroot/example.com/vendor/codeigniter4/framework/system/Database/BaseConnection.php(391): CodeIgniter\Database\MySQLi\Connection->connect()
#2 /www/wwwroot/example.com/vendor/codeigniter4/framework/system/Database/BaseConnection.php(574): CodeIgniter\Database\BaseConnection->initialize()
#3 /www/wwwroot/example.com/app/Common.php(26): CodeIgniter\Database\BaseConnection->query()
#4 /www/wwwroot/example.com/app/Controllers/Detail.php(54): get_data()
#5 /www/wwwroot/example.com/vendor/codeigniter4/framework/system/CodeIgniter.php(919): App\Controllers\Detail->index()
#6 /www/wwwroot/example.com/vendor/codeigniter4/framework/system/CodeIgniter.php(494): CodeIgniter\CodeIgniter->runController()
#7 /www/wwwroot/example.com/vendor/codeigniter4/framework/system/CodeIgniter.php(353): CodeIgniter\CodeIgniter->handleRequest()
#8 /www/wwwroot/example.com/public/index.php(79): CodeIgniter\CodeIgniter->run()
#9 {main}

Next CodeIgniter\Database\Exceptions\DatabaseException: Connection refused in /www/wwwroot/example.com/vendor/codeigniter4/framework/system/Database/MySQLi/Connection.php:229
Stack trace:
#0 /www/wwwroot/example.com/vendor/codeigniter4/framework/system/Database/BaseConnection.php(391): CodeIgniter\Database\MySQLi\Connection->connect()
#1 /www/wwwroot/example.com/vendor/codeigniter4/framework/system/Database/BaseConnection.php(574): CodeIgniter\Database\BaseConnection->initialize()
#2 /www/wwwroot/example.com/app/Common.php(26): CodeIgniter\Database\BaseConnection->query()
#3 /www/wwwroot/example.com/app/Controllers/Detail.php(54): get_data()
#4 /www/wwwroot/example.com/vendor/codeigniter4/framework/system/CodeIgniter.php(919): App\Controllers\Detail->index()
#5 /www/wwwroot/example.com/vendor/codeigniter4/framework/system/CodeIgniter.php(494): CodeIgniter\CodeIgniter->runController()
#6 /www/wwwroot/example.com/vendor/codeigniter4/framework/system/CodeIgniter.php(353): CodeIgniter\CodeIgniter->handleRequest()
#7 /www/wwwroot/example.com/public/index.php(79): CodeIgniter\CodeIgniter->run()
#8 {main}
CRITICAL - 2023-10-10 11:26:03 --> Unable to connect to the database.
Main connection [MySQLi]: Connection refused
in SYSTEMPATH/Database/BaseConnection.php on line 427.
1 SYSTEMPATH/Database/BaseConnection.php(574): CodeIgniter\Database\BaseConnection->initialize()
2 APPPATH/Common.php(26): CodeIgniter\Database\BaseConnection->query()
3 APPPATH/Controllers/Detail.php(54): get_data()
4 SYSTEMPATH/CodeIgniter.php(919): App\Controllers\Detail->index()
5 SYSTEMPATH/CodeIgniter.php(494): CodeIgniter\CodeIgniter->runController()
6 SYSTEMPATH/CodeIgniter.php(353): CodeIgniter\CodeIgniter->handleRequest()
7 FCPATH/index.php(79): CodeIgniter\CodeIgniter->run()

```
in my .env file, I set a database group named "remote".