Apple Configurator: Error 5103 when redeeming code
When trying to deploy an app purchased using the Volume Purchase Program (VPP), Apple Configurator may state “Unable to redeem code”. The detailed message includes “Please enter your Apple ID and password to redeem your code”, or “MZFinance.RedeemCodeSrvLoginRequired”, along with error code 5103.
Quit Apple Configurator, then open it again.
After entering the Apple ID and password for your iTunes account, you should be able to redeem the VPP code(s).