Make sure your smartphone and/or tablet have been updated. Every now and then they have software updates that add new features, make them run faster, fix bugs, etc. Most of the apps then also do an update to be compatible with the new software update. There are a lot of apps that want work without doing the software update…
Make sure that your smart phone and/or tablet are up to date in its software. When there is an update for phone and tablet most of the apps have to update to run with the new software update