Laravel 5.4: how to use mailbox username instead of email address for sending emails

I want to sent emails to clients from my Laravel project. Following are my mail configuration:

MAIL_DRIVER=smtp
MAIL_HOST=smtp.easyname.com
MAIL_PORT=465
MAIL_USERNAME=services@mydomain.com
MAIL_PASSWORD=mypassword
MAIL_ENCRYPTION=ssl

I could not sent emails with these settings and used to get the following error:

stream_set_blocking() expects parameter 1 to be resource, null given

I then contacted my web hosting provided. They suggested me to use the mailbox username for the email id services@mydomain.com. The mailbox username is 112627mail2. I tried but could not find an answer on how to use a username instead of the email address in mail configuration. Please help.

via Chebli Mohamed