Unlike iPhones and iPads, which are all basically the same, each manufacturer of an Android device builds it their own way, and not all of them handle email or email attachments in exactly the same. We have found a method that works on most Android devices to get the chart file you sent to your Android to show up in Astro Gold, but you need to kind of trick the device.
The chart file you send in an email is still attached to the email, and so before we can get Astro Gold to view the chart file you need to detach the file from the email. So, open the email on the Android and you should have the option to download the file. Once it is downloaded it should go into your Download folder. Open that folder, tap the chart file that is in your Download folder and it should open it in Astro Gold.
However in some cases this does not work. If it does not work for you then you may want to contact the manufacturer of your android device and tell them that you cannot open attachments that come with your emails and request that this is rectified.