How to tell if content or reputation is the problem?

Isolating content versus reputation:

Test reputation alone: Send minimal, bland content from your domain. If it still spams, reputation is the problem.

Test content alone: Send your normal content from a fresh domain with clean reputation. If it spams, content is triggering filters.

Cross-reference with data: Postmaster showing low reputation points to reputation. Clean reputation with spam placement points to content.

Historical analysis: Did placement change after a content change or after a reputation event?

Send plain cargo from your ship (test reputation). Send your cargo from a new ship (test content). Compare results.