IPhone 8 cannot open attachments

Ionic Framework
1

When I try to open any attachment, I temporarily write it to cache.

However I get an error “Unable to save” on this iphone 8. Is there a way around it or does capacitor just not work on older iphones?

public async viewFile(filename: string, fileData: ArrayBuffer, mimeType: string): Promise<void> {
        let fileUrl: string = await this.writeFileToCache(filename, UtilClass.getFileDataAsBase64(mimeType, fileData));
        if ((fileUrl || "").length > 0) {
            await FileOpener.openFile({path: fileUrl, mimeType: mimeType}).catch(async (e) => {
                if (e.message.startsWith("File cannot be opened.")) {
                    let alert: HTMLIonAlertElement = await this.alertController.create({
                        cssClass: "fp-alert",```


public async writeFileToCache(fileName: string, fileData: string): Promise<string> {
    const savedFile: WriteFileResult = await Filesystem.writeFile({
        path: `${fileName}`,
        data: fileData,
        directory: Directory.Cache
    });
    return savedFile.uri
}
2

Anyone? Clearly a major issue here.