I have a Samsung (J5/J7) device

Step 1:Open your App menu and look for "Smart Manager"

Step 2:Select "Battery"

Step 3: Select "Skooly"

Step 4: Under App optimization, select "Turned off for"

Step 5: Press back to save your settings.

Step 6: Open your App menu and look for "Smart Manager"

Step 7: Swipe to the second screen which says "Ultra data saving"

Step 8: Tap on the "+" sign and select "Skooly"

Step 9: Once you select Skooly, you will see a message like "Background data allowed for Skooly".