List channel member API giving 400, Bad Request

Hi,
I am trying to fetch channel members using: /chat/channels/{channelId}/members.
But it is returning 400 with
{
“code”: 4711,
“message”: “Invalid access token, does not contain scopes:[team_chat:read:list_members].”
}
But, I am using a server-to-server app and the mentioned scope already given.
So is there any way I can get channel member list with channel id only?