Is there any way to get insights from my Custom audiences since I can't map them?

While you aren’t able to map a Custom audience with Audience Map, you are able to do so with a Lookalike audience that is based on your Custom audience. Remember that a Lookalike audience is a much larger audience created by Facebook to “look like” the Custom audience it’s built from. So while it won’t be exact, it will give you a very good idea of the dimensions and personas in your Custom audience.

Here are the steps to follow: 

1. In Facebook, create a Lookalike audience based on your Custom audience. Keep in mind that it can take several hours (6 to 24) for the Lookalike to be fully created.

2. Once the Lookalike has completed, build a new audience in your account on Tapcast. Place the Lookalike you created into the targeting spec by selecting it from your Facebook audiences.

3. When you save the audience, Audience Map will create a map for it. You can then study the map and also get Targeting Ideas from it.