Logs are Full of [MAIL ERROR]

Your software
My Mautic version is: 2.15.3
My PHP version is: 7.0.33

Your problem
My problem is: I am bombarded with [MAIL ERROR] in my log files. more than 3 per second.

These errors are showing in the log:
mautic.ERROR: [MAIL ERROR] Expected response code 250 but got code “554”, with message “554 Transaction failed: Address length is more than 320 bytes long: ‘=?utf-8?Q?=D0=98=D0=BB=D1=8C=D0=BD=D0=B0=D1=80=2C_?= =?utf-8?Q?=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81=D0=98=D0=BB=D1=8C=D0=BD?= =?utf-8?Q?=D0=B0=D1=80=2C_=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81?= ilnar.shamsin@mail.ru’. " Log data: ++ Starting Mautic\EmailBundle\Swiftmailer\Transport\AmazonTransport << 220 email-smtp.amazonaws.com ESMTP SimpleEmailService-d-HTY7JINI1 dDJ7YLEA1YhAAKnDHyMC >> EHLO [127.0.0.1] << 250-email-smtp.amazonaws.com 250-8BITMIME 250-SIZE 10485760 250-STARTTLS 250-AUTH PLAIN LOGIN 250 Ok >> STARTTLS << 220 Ready to start TLS >> EHLO [127.0.0.1] << 250-email-smtp.amazonaws.com 250-8BITMIME 250-SIZE 10485760 250-STARTTLS 250-AUTH PLAIN LOGIN 250 Ok >> AUTH LOGIN << 334 VXNlcm5hbWU6 >> QUtJQVRaVzJLSlpaWUdUMk83NEk= << 334 UGFzc3dvcmQ6 >> QkVSVWQwRHZuSklYN0N0T3ZPZ2c0TGphc09iVnN0THR1VkRZMDNYOU5mbFM= << 235 Authentication successful. ++ Mautic\EmailBundle\Swiftmailer\Transport\AmazonTransport started >> MAIL FROM:team@healthst.com << 250 Ok >> RCPT TO:ilnar.shamsin@mail.ru << 250 Ok >> DATA << 354 End data with . >> . << 554 Transaction failed: Address length is more than 320 bytes long: '=?utf-8?Q?=D0=98=D0=BB=D1=8C=D0=BD=D0=B0=D1=80=2C?= =?utf-8?Q?=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81=D0=98=D0=BB=D1=8C=D0=BD?= =?utf-8?Q?=D0=B0=D1=80=2C_=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81?= ilnar.shamsin@mail.ru’. !! Expected response code 250 but got code “554”, with message "554 Transaction failed: Address length is more than 320 bytes long: '=?utf-8?Q?=D0=98=D0=BB=D1=8C=D0=BD=D0=B0=D1=80=2C?= =?utf-8?Q?=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81=D0=98=D0=BB=D1=8C=D0=BD?= =?utf-8?Q?=D0=B0=D1=80=2C_=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81?= ilnar.shamsin@mail.ru’. " (code: 554) (send); ilnar.shamsin@mail.ru, gwhite@healthstatus.com {“exception”:"[object] (Swift_TransportException(code: 554): Expected response code 250 but got code “554”, with message "554 Transaction failed: Address length is more than 320 bytes long: '=?utf-8?Q?=D0=98=D0=BB=D1=8C=D0=BD=D0=B0=D1=80=2C?= =?utf-8?Q?=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81=D0=98=D0=BB=D1=8C=D0=BD?= =?utf-8?Q?=D0=B0=D1=80=2C_=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81?= ilnar.shamsin@mail.ru’.\r\n"\nLog data:\n++ Starting Mautic\EmailBundle\Swiftmailer\Transport\AmazonTransport\n<< 220 email-smtp.amazonaws.com ESMTP SimpleEmailService-d-HTY7JINI1 dDJ7YLEA1YhAAKnDHyMC\r\n\n>> EHLO [127.0.0.1]\r\n\n<< 250-email-smtp.amazonaws.com\r\n250-8BITMIME\r\n250-SIZE 10485760\r\n250-STARTTLS\r\n250-AUTH PLAIN LOGIN\r\n250 Ok\r\n\n>> STARTTLS\r\n\n<< 220 Ready to start TLS\r\n\n>> EHLO [127.0.0.1]\r\n\n<< 250-email-smtp.amazonaws.com\r\n250-8BITMIME\r\n250-SIZE 10485760\r\n250-STARTTLS\r\n250-AUTH PLAIN LOGIN\r\n250 Ok\r\n\n>> AUTH LOGIN\r\n\n<< 334 VXNlcm5hbWU6\r\n\n>> QUtJQVRaVzJLSlpaWUdUMk83NEk=\r\n\n<< 334 UGFzc3dvcmQ6\r\n\n>> QkVSVWQwRHZuSklYN0N0T3ZPZ2c0TGphc09iVnN0THR1VkRZMDNYOU5mbFM=\r\n\n<< 235 Authentication successful.\r\n\n++ Mautic\EmailBundle\Swiftmailer\Transport\AmazonTransport started\n>> MAIL FROM:team@healthst.com\r\n\n<< 250 Ok\r\n\n>> RCPT TO:ilnar.shamsin@mail.ru\r\n\n<< 250 Ok\r\n\n>> DATA\r\n\n<< 354 End data with .\r\n\n>> \r\n.\r\n\n<< 554 Transaction failed: Address length is more than 320 bytes long: '=?utf-8?Q?=D0=98=D0=BB=D1=8C=D0=BD=D0=B0=D1=80=2C?= =?utf-8?Q?=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81=D0=98=D0=BB=D1=8C=D0=BD?= =?utf-8?Q?=D0=B0=D1=80=2C_=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81?= ilnar.shamsin@mail.ru’.\r\n\n!! Expected response code 250 but got code “554”, with message "554 Transaction failed: Address length is more than 320 bytes long: '=?utf-8?Q?=D0=98=D0=BB=D1=8C=D0=BD=D0=B0=D1=80=2C?= =?utf-8?Q?=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81=D0=98=D0=BB=D1=8C=D0=BD?= =?utf-8?Q?=D0=B0=D1=80=2C_=D0=92=D0=B0=D0=BC_=D0=BE=D1=82=D0=BF=D1=80?= =?utf-8?Q?=D0=B0=D0=B2=D0=BB=D0=B5=D0=BD_=D1=81=D1=8E?= =?utf-8?Q?=D1=80=D0=BF=D1=80=D0=B8=D0=B7_=D0=BE=D1=82_=D1=81=D0=BF=D0=BE?= =?utf-8?Q?=D0=BD=D1=81=D0=BE=D1=80=D0=B0_=D0=9C=D0=B0?= =?utf-8?Q?=D1=81=D1=82=D0=B5=D1=80=D0=9A=D0=B0=D1=80=D0=B4=3A_https=3A?= =?utf-8?Q?//vkitchen2premium=2Eru?= - =?utf-8?Q?=D0=BA=D0=BB=D0=B8=D0=BA=D0=BD=D0=B8=D1=82=D0=B5?= =?utf-8?Q?_=D1=81=D0=B5=D0=B9=D1=87=D0=B0=D1=81?= ilnar.shamsin@mail.ru’.\r\n”
(code: 554) at …/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Plugins/LoggerPlugin.php:140)"}

Steps I have tried to fix the problem:
I have checked my SES account and only have 50 emails sent today, which is reasonable among my accounts.
My apache logs are not showing this kind of traffic. My mautic installation is using Amazon SES for emails.

@healthstatus1 did you manage to solve this?