Mac not allowing me to download apps

Have you followed the steps as clearly described in -> Related Article: If you can't download or update apps on your Mac ?

Check also:

Check the status of your network on Mac

Check the status of your network on Mac - Apple Support

If you can't connect to the App Store, iTunes Store, or other Apple services

If you can't connect to the App Store, iTunes Store, or other Apple services - Apple Support

-> If you tried all of the above steps and you still can’t connect, contact Apple Support.