安装完后发送测试邮件，报错如下：
POST https://www.cnwm.club/api/mail/test
Swift_TransportException: Expected response code 220 but got an empty response in /www/wwwroot/www.cnwm.club/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php:447
Stack trace:
#0 /www/wwwroot/www.cnwm.club/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(360): Swift_Transport_AbstractSmtpTransport->assertResponseCode('', Array)
#1 /www/wwwroot/www.cnwm.club/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(147): Swift_Transport_AbstractSmtpTransport->readGreeting()
#2 /www/wwwroot/www.cnwm.club/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/SendmailTransport.php(50): Swift_Transport_AbstractSmtpTransport->start()
#3 /www/wwwroot/www.cnwm.club/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mailer.php(65): Swift_Transport_SendmailTransport->start()
#4 /www/wwwroot/www.cnwm.club/vendor/illuminate/mail/Mailer.php(521): Swift_Mailer->send(Object(Swift_Message), Array)
#5 /www/wwwroot/www.cnwm.club/vendor/illuminate/mail/Mailer.php(288): Illuminate\Mail\Mailer->sendSwiftMessage(Object(Swift_Message))
#6 /www/wwwroot/www.cnwm.club/vendor/illuminate/mail/Mailer.php(212): Illuminate\Mail\Mailer->send(NULL, Array, Object(Closure))
#7 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Api/Controller/SendTestMailController.php(43): Illuminate\Mail\Mailer->raw(‘wangdiandao\xEF\xBC\x8C\xE6…’, Object(Closure))
#8 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/RouteHandlerFactory.php(41): Flarum\Api\Controller\SendTestMailController->handle(Object(Laminas\Diactoros\ServerRequest))
#9 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/ExecuteRoute.php(27): Flarum\Http\RouteHandlerFactory->Flarum\Http{closure}(Object(Laminas\Diactoros\ServerRequest), Array)
#10 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\ExecuteRoute->process(Object(Laminas\Diactoros\ServerRequest), Object(Closure))
#11 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Api/Middleware/ThrottleApi.php(33): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#12 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Api\Middleware\ThrottleApi->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#13 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/CheckCsrfToken.php(44): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#14 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\CheckCsrfToken->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#15 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/ResolveRoute.php(67): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#16 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\ResolveRoute->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#17 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/SetLocale.php(51): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#18 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\SetLocale->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#19 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/AuthenticateWithHeader.php(56): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#20 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\AuthenticateWithHeader->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#21 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/AuthenticateWithSession.php(31): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#22 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\AuthenticateWithSession->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#23 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/RememberFromCookie.php(52): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#24 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\RememberFromCookie->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#25 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/StartSession.php(61): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#26 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\StartSession->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#27 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Api/Middleware/FakeHttpMethods.php(29): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#28 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Api\Middleware\FakeHttpMethods->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#29 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/ParseJsonBody.php(28): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#30 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\ParseJsonBody->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#31 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/HandleErrors.php(57): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#32 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\HandleErrors->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#33 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/InjectActorReference.php(25): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#34 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\InjectActorReference->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#35 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/MiddlewarePipe.php(84): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#36 /www/wwwroot/www.cnwm.club/vendor/middlewares/request-handler/src/RequestHandler.php(84): Laminas\Stratigility\MiddlewarePipe->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#37 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Middlewares\RequestHandler->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#38 /www/wwwroot/www.cnwm.club/vendor/middlewares/base-path-router/src/BasePathRouter.php(101): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#39 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Middlewares\BasePathRouter->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#40 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Middleware/OriginalMessages.php(42): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#41 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Laminas\Stratigility\Middleware\OriginalMessages->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#42 /www/wwwroot/www.cnwm.club/vendor/middlewares/base-path/src/BasePath.php(73): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#43 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Middlewares\BasePath->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#44 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Middleware/ProcessIp.php(24): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#45 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\ProcessIp->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#46 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/MiddlewarePipe.php(84): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#47 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-stratigility/src/MiddlewarePipe.php(73): Laminas\Stratigility\MiddlewarePipe->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\EmptyPipelineHandler))
#48 /www/wwwroot/www.cnwm.club/vendor/laminas/laminas-httphandlerrunner/src/RequestHandlerRunner.php(96): Laminas\Stratigility\MiddlewarePipe->handle(Object(Laminas\Diactoros\ServerRequest))
#49 /www/wwwroot/www.cnwm.club/vendor/flarum/core/src/Http/Server.php(44): Laminas\HttpHandlerRunner\RequestHandlerRunner->run()
#50 /www/wwwroot/www.cnwm.club/public/index.php(26): Flarum\Http\Server->listen()
#51 {main}