An API with no endpoint for the answer
Running ads into Singapore needs a verified-advertiser identity that Meta will not tell you, and rejects three different ways when you get it wrong.
- Distinct failure modes
- 3
- Endpoints listing valid identities
- 0
The requirement
An ad set targeting Singapore must carry a regulated-category declaration and a pair of advertiser identities, and they have to arrive in the same API call as the geography. Omit them and it fails.
The identity is not the Page ID and not the business ID. It is a separate verified-advertiser record.
Three ways to be wrong
Omit the identities entirely and the error at least names the problem: no advertiser information for Singapore ads.
Pass the Page ID — the obvious guess, and the ID you already have — and you get a bare 'Invalid parameter' with no explanation of which parameter or why.
Use the category and key names that Meta's own interface writes when you do this by hand, and it rejects those too, demanding a different category constant.
How the answer was actually found
There is no endpoint that lists valid advertiser identities. The API cannot be introspected for this.
So the ad set was published by hand in the interface, where a dropdown offers the right advertiser, and the resulting object was read back through the API to recover the ID.
Even then it is not directly reusable: the interface writes it with a category and key prefixes that a Singapore geography then rejects, so the category and prefixes have to be rewritten through the API while keeping the ID.