Groups audience list shows NONE in Organic Group

In my drupal site i have implemented the Organic Group module for user group management

1. Here I have created a number of groups like grp1, grp2 ... .
2. I have a custom content type as Opinion that has a field Groups audience with FIELD TYPE Entity Reference so that user can able to post the content type and choose group from GROUPS AUDIENCE to which group the post should belong

The issue is when i am adding Opinion by admin dashboard the groups are showing in the list GROUPS AUDIENCE as grp1, grp2 ... and posted to that required group

But when the authenticated user want to post that the GROUPS AUDIENCE shows NONE , by which after posting the content it is visible in Home page but not showing the corresponding group page

I have gone through this link

Also given the full permission to the Role that assigned to the user . Any guidance will help me a lot.

Thanks

I just changed the following to get my work Admin -> structure -> content type -> custom content type(i.e. Opinion) -> manage fields -> changed the WIDGET name to Select list of the field name having FIELD TYPE as Entity Reference