Mapbox not working on iOS but fine on android

Mapbox works perfectly in android but for iOS it doesn’t even display the map. It asks can the phone have access to location but that’s it. Any ideas.

 initMap(lat: number, long: number)
    let map ='map').setView([lat, long], 18);

    L.tileLayer('{id}/{z}/{x}/{y}.png?access_token={accessToken}', {
      attribution: 'Map data &copy; <a href="">OpenStreetMap</a> contributors, <a href="">CC-BY-SA</a>, Imagery © <a href="">Mapbox</a>',
      maxZoom: 18,
      id: 'mapbox.streets',
      accessToken: 'tokengoeshere'

    this.setMap(lat, long, map);

    return map;