External Collections Strategy Task Integration isn't enabled message when using RestAPI

Summary:

I'm trying to assign a Collection strategy to a Customer via the RestAPI : fscmRestApi/resources/11.13.18.05/collectionStrategies

The error response is:

This service isn't applicable because the feature External Collections Strategy Task Integration isn't enabled. (IEX-615217)

I can't find anywhere that explains how to resolve this issue, can anyone provide any guidance please?

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