I'm on a new Mojave install and I can't install updates to Apple suite programs (Garageband, Pages, Numbers, Keynote and iMovie). I've updated macOS and Xcode command line tools successfully from the Software Update app. When I open App Store, it says that I'm not signed in. (Logga in means Login in Swedish).
I try to login, but each time I enter my Apple ID password it just loads and exits the login prompt, without switching to logged in state. Note that I've logged into iCloud and iTunes successfully.
When I try to update the outdated apps. The circle loads for some minutes, and then the Update
button returns.
I've tried some different tips that I've found online, such as this, and this.