Apologies for having to repost this question. The failover is working on the RUT240, but NOT on the RUTX11.
RUTX11 Firmware 2.03.1. The RUTX11 has an OpenVPN connection to a server. I've configured failover so that if the WAN (wired) primary connection is removed, the RUTX11 switches to the SIM1 connection (secondary), and the Event Reporting so that I get an SMS when failover occurs, or returns to the Wired WAN. I have configured 2 'check IPs' (8.8.8.8 and 8.8.4.4), but only 1 success is needed for confirming that the link is up. I have noticed a couple of issues:
If the router has an active SIM connection before failover is configured, then it doesn't switch to the WAN after failover is configured, unless you disable the SIM connection. After the X11 changes to WAN, you can re-enable the SIM1, and the X11 stays on the WAN (as it should).
If you then remove the WAN connection, the X11 correctly switches to the mob1s1a1 connection (as it should), and I get an SMS saying 'Wan (wan) is down, switching to backup WAN'. However, if you then reconnect the WAN connection, I get an SMS saying 'Swtched to main WAN(wan)', but the X11 DOES NOT switch back to the primary WAN connection, (the data count on the SIM1 interface continues to climb, while the data count on the WAN connection doesn't change). Note that the System log shows the line "kern.emerg Switched to main WAN (wan)", but the data count on the interface shows indicates that this hasn't actually happened. The Wired WAN also shows as having an IP address, and being online, but the X11 doesn't appear to be using it.
If I then disable the Mobile interface, I get another SMS saying 'WAN (mob1s1a1 is down, no more backups to switch', and the X11 starts using the main WAN port (data starts increasing).
If I then re-enable the Mobile interface, the X11 keeps using the Main WAN, correctly.
As I said earlier, the RUT240 is working correctly, using 8.8.8.8 on the Mobile interface, and 8.8.4.4 on the Wired WAN interface