REST JSON

Hello there

I'm using a local variable of type java.util.List named **vkpResult ** .
When I access it from Rest API engine produces invalid Json (missing closing '}').
List size plays no role. I tryed with 1 element and with 100.

http://localhost:34435/bonita/API/bpm/activityVariable/120010/vkpResult

I'm a new in Bonita bpm. I receive data from my connector in the form as a json string.
There is like connector output param. I store this param like pool variable.
Then, i get this value with external api:

../API/bpm/activityVariable/{{taskId}}/response_rows[enter image description here][1]

I got json array like :