Hi,

Looking at Android Version History/Release note, Android Oreo OS is supported. I'm wondering if the issue is specific to Note 8 device.

This is a long short question, is there a possiblity to test this on another device beside Note 8? You can also check the ELMAH Log for any errors.

I remember having issues with some random Apps after upgrading my S7.

Try going to the K2 Application info > Storage and doing a Clear Data and Clear Cache. 

Retry the App. You will need to log in again as the App will be reset to default.

HTH

This is one of the most common problem user faces. I was having the same issue, so in order to resolve it, just follow the mentioned steps (it worked for me)

1. Un-install the app
2. Delete the cache and other files of the apps (do it via file manager)
3. Restart your phone
4. Re install the app

and the issue will be fixed. Do let me know if you are having problem performing the steps which I have mentioned above or if the problem is still there. Would love to help! :)

Regards,

9Apps // Cartoon HD // Shareit

Thanks for the valuable suggestions. I'll definitely check and share my experience.