If you go into Preferences/Web Access, you will see two IP addresses to access Express Invoice from the web. When you're using the same network access as the computer that has Express Invoice on it, use the Local Network Address. When you are at home or elsewhere, use the Internet (Cloud Access). Just save these two IP's as bookmarks on your Tab. Your log in will be the same no matter which one you use.
Check both of the boxes for local and cloud access, then click the bar to run the routing test. I've noticed on my mac that the first time I click the bar I get an error message. I click a 2nd time and it's fine. Go figure.
FYI: in the IP address, the 4 digit number after the colon is your port.
I understand there is an app for the Android, but that it doesn't sync with Express Invoice on your computer, so it's best to use the web access.
One note: I've noticed that the IP addresses occasionally change the number right before the port. If you can't get on one day, that's probably why. I've also noticed that it will randomly uncheck the local access box.
Hope this helps!