When you are logged in on the app, if you click on menu at the bottom right of the screen> then click on the cog wheel top right hand corner > scroll down and you will see the sigh out button> click that then click sigh out yes and then it will log you of the app.
You have clicked a link to a site outside of the QuickBooks or ProFile Communities. By clicking "Continue", you will leave the community and be taken to that site instead.