What is causing the StreamBuffer.php:231 error?

Question

PHP

Good afternoon.
For information. I use the Laravel framework, sending letters is carried out "on the run" (we run the script and it immediately sends the letter) or using queues (the task is queued (redis) and sent after a while).

Problem.
If sending occurs "on the run", everything is OK.
If through the queues, I get an error, the solution of which I can not find in the search engines. Maybe you have already encountered this problem and suggest a solution)

Logs:
ErrorException: fwrite(): SSL: Success in /var/www/erp.stopugroza.ru/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/StreamBuffer. php:231
Stack trace:
#0 [internal function]: Illuminate\Foundation\Bootstrap\HandleExceptions->handleError(2, 'fwrite(): SSL: ...', '/var/www/erp.st...', 231, Array)
#1 /var/www/erp.stopugroza.ru/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/StreamBuffer.php(231): fwrite(Resource id #8925, 'MAIL FROM: #2 /var/ www/erp.stopugroza.ru/vendor/swiftmailer/swiftmailer/lib/classes/Swift/ByteStream/AbstractFilterableInputStream.php(173): Swift_Transport_StreamBuffer->doCommit('MAIL FROM: #3 /var/www/erp.stopugroza.ru /vendor/swiftmailer/swiftmailer/lib/classes/Swift/ByteStream/AbstractFilterableInputStream.php(92): Swift_ByteStream_AbstractFilterableInputStream->doWrite('MAIL FROM: #4 /var/www/erp.stopugroza.ru/vendor/swiftmailer/swiftmailer/ lib/classes/Swift/Transport/AbstractSmtpTransport.php(312): Swift_ByteStream_AbstractFilterableInputStream->write('MAIL FROM: #5 /var/www/erp.stopugroza.ru/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport /EsmtpTransport.php(272):Swift_Transport_AbstractSmtpTransport->executeCommand('MAIL FROM: #6 /var/www/erp.stopugroza.ru/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/EsmtpTransport.php(348): FROM: #7 /var/www/erp.stopugroza.ru/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(452): Swift_Transport_EsmtpTransport->doMailFromCommand('[email protected] ')Swift_Transport_EsmtpTransport->doMailFromCommand('[email protected]')Swift_Transport_EsmtpTransport->doMailFromCommand('[email protected]')
#8 /var/www/erp.stopugroza.ru/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(480): Swift_Transport_AbstractSmtpTransport->doMailTransaction(Object(Swift_Message), '[email protected] ...', Array, Array)
#9 /var/www/erp.stopugroza.ru/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(189): Swift_Transport_AbstractSmtpTransport->sendTo(Object( Swift_Message), '[email protected]', Array, Array)
#10 /var/www/erp.stopugroza.ru/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mailer.php(73): /var/www/erp.stopugroza.ru/vendor/laravel/framework/src/Illuminate/Mail/Mailer.php(451): Swift_Mailer-
>send(Object (Swift_Message), Array)
#12 /var/www/erp.stopugroza.ru/vendor/laravel/framework/src/Illuminate/Mail/Mailer.php(235): Illuminate\Mail\Mailer->sendSwiftMessage(Object(Swift_Message))
#13 /var /www/erp.stopugroza.ru/vendor/laravel/framework/src/Illuminate/Notifications/Channels/MailChannel.php(64):