Facing error while posting data to api using web activity

Hi,
I am trying to get token from an url which is working fine in postman but when I try to get the same using Web activity then facing below error.

error calling the end point https://xxxxx.xxxx.xx Response status code: 'NA - Unknown'. More details: Exception message: 'NA - Unknown [ClientSideException] An error occurred while sending the request. Request didn't reach the server from the client.