The installed app keeps its own sign-in, separate from your browser. Sign in once in the app. If you sign out in your browser, you stay signed in to the app.
Common questions
Why do I have to sign in again?
I tapped Not now on the banner. How do I get it back?
On an iPhone, use the Share button as above. On an Android phone, use the three dots menu in Chrome as above.
How do I remove Sideline from my phone?
Touch and hold the Sideline icon, then choose the option to remove it. Your account and your club's information are not deleted.