com.apple.commerce.client error 500
My MacBook Pro 13" has just come back from the SSD repair program (https://www.apple.com/support/13-inch-macbook-pro-solid-state-drive-service-program/) with the latest version of Mojave.
Now, AppStore doesn't let me to sign in or download anything, I'm receiving the message of "com.apple.commerce.client error 500".
I have tried to restore the system (re-installing the latest version), using a test user and to connect on different Wi-Fi's. Also contacted to Apple Customer Service numerous times.
Have anyone been able to fix this problem yet?
MacBook Pro 13", 10.14