Iphone screen doesn't show the title

Hello i have made a webapplication with angular/ionic but the title doesn't show up on iphones, only on the android phones. I am using ion-title.

<ion-header>
  <ion-toolbar>
    <ion-buttons *ngIf="(checkTablet$ | async)" slot="start">
      <ion-menu-button></ion-menu-button>

      <ion-title>Portfolio</ion-title>
    </ion-buttons>

    <ul *ngIf="(checkTablet$ | async) === false">
      <li>
        <h5>Portfolio</h5>
      </li>

      <a routerLink="/home" routerLinkActive="active">Home</a>
      <a routerLink="/about" routerLinkActive="active">About</a>
      <a routerLink="/work" routerLinkActive="active">Work</a>
      <a routerLink="/contact" routerLinkActive="active">Contact</a>
    </ul>
  </ion-toolbar>
</ion-header>