I saw this as a closed issue, but I am having the same problem. I get through all the steps and start installing on my smartthings app. I have a co-worker who has this working on his iPhone to compare it to as I go.
When I get to the Connect to MyQ page on the app, I have the Advanced options greyed out while he has those options available. In other words, I don't have the Contact Sensor or Acceleration Sensor options. He does but he doesn't have them selected.
I enter my user email and pw and choose Chamberlain as the Gateway brand and it takes me to the next screen.
It asks me which devices to connect. I get Garage Door Opener and a blank box which I assume is the lights. I click them both, or either one, it doesn't matter. I click done and get a green box at the top that says, MyQ (Connect) is now installed and automating. But the screen does not go away and I get a red box that says Failed to save page: prefListDevices
UPDATE: We just got it working, (sort of) but I hope to post this here in the hopes that it may help others. We THINK that the problem was that my HUB was not yet registered. I'm pretty sure we DID do that, but it may not have taken for some reason or another. Once we saw that I did not show a hub on my page here, we added the hub and that seemed to do the trick.
ALSO: I had a half dozen MyQ Connect Smart Apps at this point that I needed to delete. So make sure you don't have that also.
UPDATE 2: I still don't have Alexa functionality. I have some weirdness going on. First, as I mentioned above, I have TWO MyQ:Connect Devices. One is blank and I assume it is the light? The other is the Garage Door opener. When I ask Alexa to open my Garage Door she thinks I am crazy. She tells me to name the device and the action. I've tried Alexa, Garage Door Open and that doesn't work either.
The Alexa smart app is installed and both MyQ things are seen and recognized by Alexa but she doesn't do anything with them. I gotta say, this is some really heavy lifting for most people and is sure not ready for prime time. Most of my friends wouldn't touch this with a 10 foot pole and I might not would have if I had known what I was getting into. I was better off with Wink for most things. But I wanted ALEXA to do everything, LOL. If you leave this open I will come back and post if I find out what I'm doing wrong now. My hope is that this will help someone else in the future.
UPDATE 3: I've managed to really screw things up. I got home and talked with my friend, he said to change the name from MyQ:Garage Door Opener to Garage Door. I did that. It worked. Well, Alexa would OPEN the door but not shut the door. This got me to wondering if maybe the other blank MyQ was CLOSE the door. So I named it Garage Door also. LOL. Every time you change anything, you have to tell Alexa to REDISCOVER everything.
So I created a paradox. I ended up losing everything. My entire MyQ:Connect app was blank again so I had to re-enter my credentials and brand of Gateway. THIS TIME I am able to see the ADVANCE sensor options. I don't know if I should mess with them. So I'm kind of back to square one, except I should add that adding the garage door to Smartthings seemed to have taken it OFF of WINK so when I got home I couldn't get the garage door to open through WINK and had to use Smartthings.
What a mess!