If you are using Magento 2.2.4 or higher, either fresh or upgrade from 2.2.3, there is a bug that alters the email sender name. It will change from your presence in the store configuration General->Store Email Address to the server usernames. Something like this:

2.2.3 – [email protected]

2.2.4 – [email protected] or on Stratus this might be www-data@…ikodes.net