Is the App Store available?
Check Apple’s System Status page to find out if the App Store is temporarily unavailable in your country or region.
Manually update the app
Open the App Store and update the app manually.
Learn what to do if a message says that you can't connect to the App Store.
Change your payment method
You might have an unpaid order. To fix the issue, change your payment method. If you can't change your payment method, you can redeem a gift card and use the balance to pay for any unpaid orders.
Restart your Mac
Restart your Mac. Then check whether you can download or update apps.
If you still can't download or update apps on your Mac, contact Apple Support.