"This product has been identified as a strong magnet or strong magnet set that does not comply with Amazon policy." on Amazon: what it means
The poster reproduces a strong magnet restriction and asks how to address the identification. The Amazon reply asks for a support case to investigate further. If your product has loose magnets within the applicable size range, its magnet testing needs checking.
The things you must have
General Certificate of Conformity (GCC): You issue this yourself using test results.
Country of origin marking: Ask your factory.
Importer registration and customs bond: Your broker files CBP Form 5106; they'll arrange bonds for formal entries.
Check these first
If your product has loose magnets that fit the regulated small parts cylinder, ask your factory for the magnetic flux testing relevant to those magnets. If your magnetic product needs its testing reviewed, check the magnetic flux results with your factory when collecting the safety evidence for the supplied magnets. If your magnetic product is intended for children, you'll need its Children's Product Certificate when asking your factory for the paperwork covering that children's product. If your magnetic product is intended for children, ask your factory for the CPSC accepted laboratory report supporting the product safety documents for that product. If your magnetic product is a children's toy, ask your factory which toy safety standard applies when reviewing the rules that cover those toy magnets.