CRM 2016 R1 datatype "Customer " not supporting adapter 5.5.4

I am using data type contact in one of my custom entity. When I am trying to insert data using Scribe Adapter I am getting error message: "Attribute regardingcustomeridtype must not be NULL if attribute regardingcustomer is not NULL". I am mapping regardingcustomer with contact guid and regardingcustomeridtype =2.

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