EA is working to resolve the issue with redeemed PS4 codes not allowing download of beta.
EA_David (Community Manager) said:Hi guys, I've gotten some updates on this, I'll just paste in the info I have.
Xbox One: Some users have found that their pre-order codes won't work, and appear as invalid. We are investigating this, so please just hold onto your codes for now.
PS4: Pre-order codes can be redeemed but don't give access to the Beta. We are investigating this and you don't need a new code.
Origin: Some users who pre-ordered from the store during a certain period might not have automatically gotten in. If you have a pre-order from before October 2nd but don't have access, please email support using the steps here: https://help.ea.com/en-us/help/star-wars/star-wars-battlefront-ii/star-wars-battlefront-ii-beta-trou...
Thank you for your patience, we hope to have an update soon.