Resetting internet connection fix this in my case.
Just had this happen to me on PS4:
What I think caused it: Left campaign running, unplugged my internet wire(needed it for the computer), came back an hour later, reconnected wire, connected to the PS4 network but never quit out to reconnect to the EA servers.
I completed the remaining 5 campaign levels and 2 collectible challenges -- These boxes are greyed out and not marked as redeemed but I cant collect them.
I also completed 2 Multiplayer challenges and cant collect those rewards
Ranked up from level 32 to 33, It showed in game I received 2000 credits for this, however, upon returning to the main screen, I only received 600 credits from completing Galactic Conquest multiplayer stage
Ranked Phasma from 15 to 20 in the cards and the Victory Pose 4 still hasn't unlocked.
Tried hard resetting PS4, resetting internet, restarting and quitting campaign mission - Still won't let me collect rewards.
This is very annoying. I spent hours this morning playing Starfighter Assault to rack up kills for the Last Jedi Challenges and none of them counted towards it. Also completed a milestone for Phasma and couldn't claim the reward.
After the daily reset, everything un-greyed out and I even received the level up credits too.
Looks like you just have to wait for the Battlefront 2 servers daily reset for it work again
