Error 403 - Creating Campaign

Hi,

I'm having issues with creating a campaign. I get the following error:
{"http_status":403,"message":"Requested action is forbidden","message_code":"api.action.forbidden"}

I'm sending a post request to https://backstage.taboola.com/backstage/api/1.0/account_id/campaigns/, where account_id is the alphabetical account ID. Do you have any ideas of what would be causing this issue?

Thanks,
Jerry