Hey there Tigre12,
Thanks for reaching out to Apple Support Communities. I understand you’re having issues downloading apps from the App Store on your Mac. I’ll be happy to help with this.
To verify, what happens when you attempt to download an app? Do you get any error messages? If you have another device, like an iPhone or iPad, can you download apps on it?
If you haven’t already, restarting your Mac can be a good place to start for this issue:
How to turn your Mac on or off
If that doesn’t help, try downloading an app from a different network. Also, check for any service interruptions reported at the Apple System Status page:
System Status
Next, make sure the Date & Time preferences are correct:
If the date or time is wrong on your Mac
You can find more info that may help here:
If you can’t download or update apps on your iPhone or other Apple device
Regards.