We also have the digital version. As others have stated it seems to eventually start working randomly days or weeks later but I have been able to get around the issue fairly consistently by doing the following.
Delete the latest save files for Minecraft under the ps4 system application data.
Create a new user on the ps4 and start Minecraft under that new user. The game will start but wait until it completely loads. I usually create a new world as well just to make sure it's working
Switch back to the user you were using before and start Minecraft.
It will reset the link to the xbox live account and you will need to re-link the account when signing in.
We also have the digital version. As others have stated it seems to eventually start working randomly days or weeks later but I have been able to get around the issue fairly consistently by doing the following.
Delete the latest save files for Minecraft under the ps4 system application data.
Create a new user on the ps4 and start Minecraft under that new user. The game will start but wait until it completely loads. I usually create a new world as well just to make sure it's working
Switch back to the user you were using before and start Minecraft.
It will reset the link to the xbox live account and you will need to re-link the account when signing in.