Ionic - EACCES (Permission denied) error when uploading video

I'm having some difficulties trying upload video file to server using Cordova Camera Plugin and cordova-plugin-advanced-http. The code works like a charm when uploading an image from gallery, but no matter what I do, I always receive EACCES (Permission denied) when uploading a video from gallery:

file url ->  file:///storage/emulated/0/DCIM/Camera/VID_20200908_114957.mp4
post-post-module-es2015.js:240 {status: -1, error: "There was an error with the request: /storage/emulated/0/DCIM/Camera/VID_20200908_114957.mp4: open failed: EACCES (Permission denied)"

Looking only at the error message, we can conclude it's a permission issue, so I tried use cordova-plugin-android-permissions and request READ_EXTERNAL_STORAGE permission. No success, the app has the permission but the error remains the same.

This is part of the code used to upload

private chooseContentUsingCameraPlugin(SOURCE: number) {
    const options: CameraOptions = {
        destinationType: this.camera.DestinationType.FILE_URI,
        mediaType: this.camera.MediaType.ALLMEDIA,
        sourceType: SOURCE
    };
    this.camera.getPicture(options).then((contentUrl: string) => {
        if (contentUrl.indexOf('://') === -1)
            contentUrl = 'file://' + contentUrl;
        const queryIndex = contentUrl.lastIndexOf('?');
        if (queryIndex !== -1)
            contentUrl = contentUrl.substring(0, queryIndex);
        console.log('file url -> ', contentUrl);
        this.startUpload(contentUrl);
    }, (err) => this.onUploadError(err));
}

private startUpload(fileUrl){
    ...
    this.nativeHttp.uploadFile(req.url, null, headers, fileUrl, fileName).then(res => {
        let data = res.data;
        if (res.data && (req.responseType === undefined || req.responseType === 'json'))
            data = JSON.parse(res.data);
        console.log(data)
    }).catch(error => {
        console.log(error)
    });
}

can someone explain what could be causing this issue?

from Ionic - EACCES (Permission denied) error when uploading video