Need Linux security expert to stop hacker using my SMTP provider

Job ID: 33879568

Budget: $15 – $25 USD

I am using Sendgrid to email correspondence with members. I have software written in Laravel that uses a env file. Hacker signs-up for membership, and somehow hacks and uses my IP to mail from since Sendgrid restricts by IP.
Related categories: PHP System Admin Linux Apache Internet Security