GetExternalContactAction lookup failing with 404 on valid numbers

Hey folks,

Running into a wall with the GetExternalContactAction in Architect. I’m trying to do a simple lookup by phone number before routing, but it keeps bombing out with a 404.

I’ve double-checked the external contact store ID and it looks right. The numbers are stored as E.164 in the store, and I’m passing them in the exact same format. Here’s the config I’m using in the Data Action:

{
 "type": "GetExternalContactAction",
 "settings": {
 "externalContactStoreId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
 "lookupKeys": [
 {
 "key": "phoneNumber",
 "value": "{{trigger.phoneNumber}}"
 }
 ]
 }
}

The trigger.phoneNumber is definitely populated when I test it. I even added a debug step to print it out and it shows +15551234567. But the action returns notFound every single time.

I tried hitting the REST API directly via Postman to see if the contact actually exists and the API returns the record just fine. So the data is there. It’s just the Architect action that can’t see it.

Is there something weird about how the lookup key is matched? Or maybe I need to specify the field type explicitly? The docs are pretty thin on this one.

Appreciate any pointers.