I have a problem with REST (integrationHub)

[antoine gremill]

Hi there,
I have a problem with REST (integrationHub).
I have a REST API that must return tasks to me, so for that I make a data source, 
I configure it in TYPE: REST(integrationHub), Format: JSON.now that the data source is created, 
I will do the request action.
the problem is there.
once the action request has been created, I automatically get input variables, which is normal,
there is : LIMIT, OFFSET, LAST SUCCESS IMPORT TIME, IMPORT START TIME.
until nothing abnormal is like in the doc.
but in doing so, I don't add a fifth ( ATTACHMENT NAME ) and this variable is mandatory.
so when I test my flow, I get this error: NAME FOR ATTACHMENT TO STORE RESPONSE MISSING.
in fact I don't know what to put in this variable, not where it comes from.
I thought of a movais configuration, but even on my dev instance it's the same.
so my questions.
what is 'Attachment Name'.
is how i have to use myself?

thank you in advance for your help !

[Sai Kumar B · Accepted solution]

@antoine gremillet 

I believe you have made Attachment input as mandatory in doing so its popping-up an error when you submit with empty input

[antoine gremill]

in fact, if I delete it or that I but not mandatory or that I enter 
a name at random, it always returns the same error