I am new to this Instagram API, and I read their doc about endpoints, this is the endpoint that I am using:
/v1/tags/{tag-name}/media/recent?access_token=ACCESS-
You can try it and it is working for me.
/v1/tags/{tag-name}/media/recent?client_id={YOUR_CLIENT_ID}
My client id is created before "permission review", it is working now and I am trying to submit permission review to Instagram now, hope it will pass.