People's pension error message:
D/W14 - AE Date has not been provided and worker group does not support postponement although employee has an AE status set to 'Eligible'
The issue is caused by at least one pair of worker Group ID and worker Group description being the identical when the scheme was set up with People's.
People's Pension's support team should be able to edit the Worker Group description (leave the ID as it currently is) and change the description to be anything that is different from the ID (e.g. put a 1 at the end or something). Once that update has been made, you should be fine to process through pensionsync.
Premium users of pensionsync can contact pensionsync support and we will contact People's Pension to arrange the required change.