Such an issue may happen if there's not enough memory space on your device. Also, we recommend checking whether Storybeat has access to your Photos.
To do that go to Settings > Privacy > Photos > Storybeat > Read and Write on your device.
To do that go to Settings > Apps >Storybeat> Permissions> Storage Make sure storage is active.
Try to uninstall and install again, close all other applications when you are using Storybeat and remember to update the latest version so that you can enjoy all the features that Storybeat has for you.