Body not taking whole device width on mobile device

Question

When the page is displayed on PC or tablet width it works perfectly. When on phone the body leaves empty space on the right. It isn't margin, or padding. I have tried width: 100% and width: 100vw.

Although the @media part doesn't help too much. I'm using flexbox to position everything, the viewport is activated and I have tried using position absolute / fixed on the body, but nothing works.

@media (max-width: 576px) {
  body {
    width: 100%;
  }
  main {
    width: 100%;
  }
  header {
    justify-content: center;
    flex-wrap: wrap;
    padding: 1rem;
  }
  nav {
    margin-right: 0px;
  }
  a {
    margin: 0.5rem;
  }
}