Why is there no sound from ios devices after compression with ffmpeg?

Question

fmpeg

I compress video using Laravel library for FFMPEG.

$lowBitrateFormat = (new X264('aac', 'libx264'))->setKiloBitrate(700);

        FFMpeg::fromDisk($this->video->disk)
            ->open($this->video->path)
            ->addFilter(function ($filters) {
                $filters->clip(TimeCode::fromSeconds(0), TimeCode::fromSeconds(30));
            })
            ->export()
            ->toDisk('local')
            ->inFormat($lowBitrateFormat)
            ->save('public/downloadable/'.$this->video->id . '.mp4');

Everything is fine in the browser and through Android, when I go through the iphone or ipad there is no sound. I tried different audio codecs, nothing helped.
How can I fix this?