Copy Data Activity Failed with Unreasonable Cause

It is a simple set up but it has baffled me a lot. I'd like to copy data to a data lake via API. Here are the steps I've taken:

• Created a HTTP linked service as below:

• Created a dataset with a HTTP Binary data format as below:

• Created a pipeline with a Copy Data activity only as shown below:

• Made sure linked service and dataset all working fine as below:

• Created a Sink dataset with 3 parameters as shown below:

• Passed parameters from pipeline to Sink dataset as below:

• That's all. Simple, right? But the pipeline failed with a clear message "usually this is caused by invalid credentials." as below:

Summary: No need to worry about the Sink side of parameters etc. which I have used same thing for years on other pipelines and all succeeded. This time the API failed to reach a data lake from source side as said "invalid credentials". In Step 4 above one could see the linked service and dataset connections were succeeded, ie. credentials have been checked and passed already. How come it failed in data copy activity complaining an invalid credentials? Pretty weird. Any advice and suggestions will be welcomed.