Clearing the app cache is kind of like a cleanse for your apps. It will get rid of residual files that could slow down the app and cause connection issues.
If you have an iPhone, please proceed with the following steps:
1.    Go to Settings > General > iPhone Storage.
2.    Scroll down to the list of apps and tap on one that you want to clear.
On your Android phone, please follow the steps below.
1.    Go to Settings
2.    Swipe to App & Notifications and tap Apps
3.    Select the app you want to clear.
4.    Tap Storage, and then tap Clear cache.
If the steps are a bit different on your device, you may need to Google your specific device about how to clear the App cache.