Getting error "Consumer instance not found" while seek to beginning using rest proxy even though giving correct consumer instsnce Id

Question

I am new to kafka, I am trying to seek to beginning by using kafka Rest Proxy using /consumers/(string:group_name)/instances/(string:instance)/positions/beginning

Could anyone please clarify about below:

1)I am assuming that the consumer Instance Id is the "Consumer Id" which is displayed on confluent UI(Control Center) under selected Consumer group. is it the correct way to find consumer instance id?

2. if (1) is correct then I am passing the correct consumer instance Id to "/consumers/(string:group_name)/instances/(string:instance)/positions/beginning" but getting error like below. { "error_code": 40403, "message": "Consumer instance not found." }

can anyone please help me to resolve this issue.