"Token type is not allowed" error on sharepoint search API

[Aniket_Nade]

Aim:- To access sharepoint through REST Api

Steps taken:- 

1. Created site on sharepoint.
2. Registered site as an app using https://<<domain>>/sites/<<site name>>/_layouts/15/appregnew.aspx
3. Granted tenant scope permission using https://<<domain>>/sites/<<site name>>/_layouts/15/appinv.aspx
4. Permission xml used
5. <AppPermissionRequests AllowAppOnlyPolicy="true">
     <AppPermissionRequest Scope="http://sharepoint/content/sitecollection/web" Right="FullControl" />
   </AppPermissionRequests>

     4. Collected app identifier from  https://<<domain>>/sites/<<site name>>/_layouts/15/appprincipals.aspx

     5. Fetched access token using https://accounts.accesscontrol.windows.net/<<tenant id>>/tokens/OAuth/2/

     6. Tried to search using https://bhyve10.sharepoint.com/sites/Tech/_api/search/query?querytext='smart'

          Headers

          Content-Type:application/json;odata=verbose

          Accept:application/json;odata=verbose

          Authorization:Bearer <<access token from step 5>>

         Got below error message

          {"error":"invalid_request","error_description":"Token type is not allowed."}