Meta rejected the creative with a generic message. This usually happens when the original ad is a "leads via messages" ad and the destination ad set was recreated to optimize for Conversations: the chat form from the original ad doesn't work for Conversations. Ads Editor already adjusts the creative automatically.

How to fix it:

  1. The system already adjusts the creative automatically, so try reprocessing.
  2. If it persists, recreate the ad manually in Meta Ads and choose the messaging destination you want.

If it keeps failing in Ads Editor, contact support and include the account, the ad set, and the source ad.