After trying for months now to get my Fanvil G100S ATA to register on Mweb VoIP, I wish to share my hard found success: (Will the experts please bear with us novices)
When configuring the ATA, use an ethernet cable between the LAN port on the ATA and the ethernet port on PC. Login, HTTP:/192.168.10.1, and head to the VOIP tab, line 1, basic settings. Using the expert advise given above, thank you much, I found success with the following settings:
Server address 126.96.36.199 (for I live near Cape Town)
Server port 5060
Authentication user 2787xxxxxxx
Authentication password ************
Phone number 2787xxxxxxx
Display name 2787xxxxxxx
Enable registration tick
Select APPLY and notice that registration FAIL/show UNAPPLIED, for reason that the ATA is not connected to the internet (because of the LAN connection).
Logout and switch ATA off (unplug). Now use the ethernet cable between WAN port on ATA and LAN / WAN port on the router (I use Huawei B618 on RAIN network). Plug in and it registers itself. Plug in normal analog landline phone and you should be good to go.