If you are using a free domain (e.g., Gmail, Yahoo, AOL) for your From email address you may run into issues with deliverability. Free email services have specific policies in place to prevent spam that can cause delivery issues.
To help with this issue, for all Free users that use a free domain for their From email address we add an extension to your From email address - send.pushsendmail.com. For all paid users we add the extension pushsendpro.com.
This will ensure the From email address will match the domain the email is being sent from and thus help deliverability.
If you don’t want to use this From email address you can create a new Sender or set up a custom domain.