Responsive Image Module is only selecting fallback image style I recently tried implementing drupal 8's Responsive Images Module.
I studied about it's basics and implemented according to the guides available online. But when i try to use it on any image on the site, its only selecting the Fallback Image Style. I have defined 5 breakpoints and 5 image styles for each breakpoint. 

My breakpoint.yml is as follows:

investindia.big_screen:
  label: big screen
  mediaQuery: '(min-width: 1025px)'
  weight: 4
  multipliers:
    - 1x
investindia.tablet_landscape:
  label: tablet landscape
  mediaQuery: '(min-width: 769px)'
  weight: 3
  multipliers:
    - 1x
investindia.tablet:
  label: tablet portrait
  mediaQuery: '(min-width: 481px)'
  weight: 2
  multipliers:
    - 1x
investindia.smalltouch_landscape:
  label: smalltouch landscape
  mediaQuery: '(min-width: 321px)'
  weight: 1
  multipliers:
    - 1x
investindia.smalltouch:
  label: smalltouch portrait
  mediaQuery: '(min-width: 1px)'
  weight: 0
  multipliers:
    - 1x


Edit : Adding my responsive image style configuration for further clarification on the issue.
The posted responsive image configuration seems correct. Remember that you also need to change the image field formatter to "Responsive image". If you are using image fields on node entities, you can do this at

/admin/structure/types/manage/MY_NODE_TYPE/display/MY_VIEW_MODE

(If you are using image media entities instead of image fields, use the "Rendered entity" field formatter on the node, and switch to the "Responsive image" field formatter on the media entity at /admin/structure/media/manage/MY_MEDIA_TYPE/display/MY_VIEW_MODE )