SharePoint 2016 InplaceSearchQuery cant Work in _layouts/15

I’m new to SharePoint.

When I using the InPlaceSeach in SharePoint it’s does not shown me the results as I want.

Its only display the all the items in my list without filtering.

Here with SharePoint InPlaceSearch Query. The Query had any wrong?

https://mvponduty.com/XXXX/XXX/XX/_layouts/15/inplview.aspx?List=9cf05e04-45bc-4ef1-9ed8-b75a71a9010f&view=4993B60A-BBCE-4A67-BF93-EFE3E405019D&InplaceSearchQuery=Devops 

Getting 401 HTTP Unauthorised for file under _layouts/15

Attempting to retrieve a file from Sharepoint using guidance from this page

https://docs.microsoft.com/en-us/sharepoint/dev/sp-add-ins/working-with-folders-and-files-with-rest#working-with-files-by-using-rest

generally works.

I can access these types of files programmatically(download them locally): “server/sites/site/folder/subfolder/myfile.xlsx”

However: “server/sites/site/folder/_layouts/15/Doc.aspx?sourcedoc=entry&file=myfile.xlsx”

has beeen annoyingly inaccessible for me – all I get is:

HTTP/1.1 401 Unauthorized

I can access the file in my browser without any issues. What am I missing here? I cannot find any references in the documentation nor online on what else to try here.

It is a requirement that I retrieve this file with a REST request and to download them locally.