I clear the caches of my individual apps every few weeks. The phone reminds me if I forget. I use the app named Smart Cleaning that's a system app. It came with the phone and isn't on Play Store. It cannot be uninstalled. It's been working perfectly until today. It can't clear Instagram's cache. When I go to Instagram's app page, it wont clear manually.

I've tried Google but all I found was what I know; go to the app page, then to Storage, then tap Clear Cache.
Any other ideas would be appreciated.
Thanks in advance,

 

Thanks for the help and I apologize for not being clear enough. The Smart Cleaning app isn't on Play Store and cannot be uninstalled. That is the issue.

 

Duh! I needed to reinstall my brain first.
Thanks, that did it.