Yup 401 indicates authentication issue. is this sub account already working on another device? I would verify the user/pass with something like linphone (software client) so that you can confirm it's the correct pass. Also for testing you could setup a new sub account for testing. Usually for these issues it always came down to the user pass not being correct on my end. Using linphone or xlite I can always verify if those details are correct to narrow in on the issue. Just for testing as well I would remove the realm I didn't need it to authenticate to voip.ms.
