I downloaded the Quickbooks online desktop app. It was working at first, but the stay signed in option has disappeared. I've already tried uninstalling and reinstalling.

Hello pmwehrle,

Welcome back to the Community. It's important you're still able to use QuickBooks to track your income and expenses among other amazing features offered in the program. I'll be happy to share more information so you can continue being great at managing your business. 

The QB Online Desktop app is no longer supported in Canada. I suspect you may have downloaded the US version of the app which is available online. It's vital to note that the US app is only compatible with US QB Online accounts only. That being said, you can still access your account by visiting www.qbo.ca on a web-browser. Once you're on the site, look for the Sign-in option at the top right side and enter your login information. Once you're logged in you'll be able to access your info and use QuickBooks as normal. 

In case you have other questions, don't hesitate to get back to me in the comments below. I've got your back.