Okay so a number of time I have seen people asking for help on app not working or correctly and each time the the reply is the same on how to fix the issue, it's about clearing the cache and data here is a video on how to do this.
(Hope this will save you some time on asking a question and having to wait on a answer)
For the Samsung S8
https://www.youtube.com/watch?v=MzFSFAqftus
For an Older Samsung
https://www.youtube.com/watch?v=c3K4hZu1ai8&feature=youtu.be
How to Clean App Cache on Samsung Galaxy S8 and S8+
- Open the app drawer
- Look for ‘Settings‘ and tap on it.
- Then Tap on Apps->App Manager
- Now, select the app you want to clear off the cache.
- Now tap on ‘Storage‘.
- And then tap on ‘CLEAR DATA‘ to clear its cache memory.
If you would like to perform this task for all installed applications, this can be done easily. Follow the below steps:
- From home, tap on ‘Apps‘.
- Tap on ‘Storage‘.
- Select the ‘Cached Data‘ and confirm it to clear entire cache on the Samsung Galaxy S8 and S8+.
Hope it helps! 
