LOOKALIKE_SOURCE_TOO_SMALL Lookalike Source Audience Too Small

The source audience for your lookalike audience doesn't have enough members. TikTok requires at least 1,000 matched users in the source audience to build an effective lookalike.

What causes this error?

The source audience for your lookalike audience doesn’t have enough members. TikTok requires at least 1,000 matched users in the source audience to build an effective lookalike.

How to fix it

Grow your source audience before creating the lookalike. You can combine multiple custom audiences into a larger source, use a broader conversion event window, or use a higher-funnel event (e.g., ViewContent instead of Purchase).