I have been meaning to write this for a long time now and I hope it helps others.
My initital sync problem was not obvious (see history below) but now I know why it happens and I can work with it. This is my first smart phone and I did not realize that my phone goes to a lot of effort to conserve battery power. In my case my phone disabled WiFi when ever I "locked/closed/blacked out" the home screen. Locking the home screen means pushing the power button and letting the screen turn off; turn off to the the point were I need to enter my password to use it again. Turning off also includes timing out were it blacks the screen.
To get the WiFi back on I have to "use" the WiFi and then the phone powers up the WiFi and everything works fine. As it turns out using the WiFi includes asking MLO to sync with my PC. Powering up the WiFi takes several seconds and in that amount of time MLO would time-out waiting for a connection. By the third attempt the WiFi was ready and MLO would sync.
In working with this issue I learned that the WiFi can be set to not power up if the phone is locked and on battery power. I have tried the setting to always have the WiFi on but this will drain my battery over night because it is always checking for updates, the weather, etc.
The bottom line, whenever I need to sync with MLO I verify that the WiFi icon is present my notification area and them my sync works first time.
The history for this problem is this; When I setup sync, I would go through the steps to pair my phone with my PC and that would work fine. (As a side note, since I was not aware of what the WiFi icon was telling me at the time I don't recall if it was present or not during pairing.) As the last step in pairing, MLO would ask if I wanted to do a sync and I would answer yes. The sync would succeed. The fact that it succeeded proved to me that everything was setup correctly; it should work every time, all the time. Typically a few minutes later I would try to sync and it would fail. I would try again, it might fail it might work. In frustration I would try a third time and most of the time it would succeed. MLO support was patient and tried to help but they would tell me something was wrong with my settings and check my IP etc. but I knew the settings were correct because I did a successful sync.
Then several months later when I learned more about my phone I started noticing the Wi-Fi icon coming on or not present and I made the connection that the reason my sync failed was that the WiFi was not powered up. Today when I tried to recreate the problem I can't seem to get the WiFi to stay powered off for more than 15-20 seconds after unlocking my phone and so I was not able to recreate the problem. :(
Please note that my phone is an "old" 2.2.2 Android. This may not be an issue for newer 2.3.xx and above phones.