There are typically 4 or 5 standard issues we would need to explore. This is standard for all the issues people have:
1: First have them turn off their device for 5 minutes and then reboot.
2: If they have a 3G or 4G connection, they need to disable that and ensure that they have Wifi connected. Typically coffee shop Wifi’s limit the download and upload speed to accommodate multiple users. So they should have their own personal Wifi or use a friends Wifi network.
3: They they should click on this link: https://rink.hockeyapp.net/apps/bfbccfac3f441cc82a0c5f676de7b8c0 and start the download process.
4: There may also be an issue that they have too many Apps open and running in the background of their device. This impacts the device performance tremendously. These should be removed from the cache files. Click the home button once. Then double click the home button twice and all the apps that are currently open will appear half the size of the screen. Then using your finger, you drag these apps to the top of the screen and they will disappear, removing them from the cache files. You are not deleting the apps, merely removing them from the system resource memory.
5: If a “waiting text” appears and there is no installation process occurring, try clicking on the waiting button to begin the install procedure. If this does not work, then again reboot the device and click on the “waiting” icon again and this should start the installation process.
Please try the above and let me know the outcome