not really sure where you are going wrong ....

the app works the web site, right? You send your plans to [email protected] from the email address you registered with the web site, then you get an email saying your trip is ready, you check it and edit as necessary on the web site, then once that is done, you link the app to your account on the web site with the same email address/password (you only need to do that once, it has to be exactly the same), and it should update with all your trips. Once you have linked the app to your tripit account, it should update whenever you open the app, if you have a wifi connection.

There is no need to give it access to your gmail account unless you wanted to do that.

The only thing pro does over non-pro is that pro will monitor your trips and send you a bunch of notifications about when to check-in, gate announcements, delays, etc. But those are things you can also get directly from the airline also in most cases, if you register for flight notifications with each airline that you fly and make sure the airline knows its you flying on that segment. (by FF# or other registration methods.) If you fly on one airline 99% of the time, pro doesn't do a lot for you. If you frequently fly on different airlines with mixed segments, etc, than pro might be worth it for you. You can get Pro free with a bunch of third party things. (Amex Platinum for example, IIRC.)

-David