Update. Got the new Rogers Ignite modem and set it up successfully. I think the modem is actually XB7 (Ignite Gen 2 - white color), as the XB6 is in black color. I didn't see any "option" under the Advanced tab and couldn't find anywhere to enable/disable the SIP from the user interface. However, it seems my OBI200 works ok i.e. it can dial-out and receives call. There are 2 possibilities: the SIP is disabled by default in the XB7 modem or it is enabled but it doesn't or hasn't caused the issue yet. Perhaps, they figured out and improved the SIG ALG protocol on this modem. Anyway, I will keep monitoring my OBI200 for now.