I can't find the same function in the premium APP. I guess it doesn't do this?
I'm stuck Tried your suggestion setting Master to MTH and it seemed to work, accept for #3 Wifi unit. But app, while seeing the MTH network didn't pick up any TIU's?
If the Subnet Mask on each Wifi unit was set to blank, due to my stupidity, how do I correct that? Or does it need correcting?
You need to go back to "square 1".
My suggestion is that you call MTH and ask a tech to help you reset all 3 WIUs back to their true factory settings.
Then, set the WIUs up in a basic configuration without doing any fiddling with settings. That will establish a baseline before you modify anything that you shouldn't.
Further, unless you have a high confidence that you understand how things work, stay away from LuCI in the future, except for firmware updates. While adjusting settings may allow your WIUs to come online a bit faster, the down side is, as you
You've learned, the hard way, that by using LuCI to adjust WIU settings, you can cause serious self-inflicted problems.
Agreed, big mistake touching LuCI. Because ever since I did that the Wifi units have not been reachable.
I will email you on contacting MTH