Hello there, @N1nja.
It's nice to have you in the Community. I'd be happy to help share some solutions to log in to QuickBooks Online via phone browser.
Since you're able to log in using the computer, let's try clearing the cache to fix any damaged files within the program's installation.
- At the top right, click Help.
- Select Reset App Data.
This will clear the cache and reset the app to the QBO sign-on screen. If you get the same result, you can uninstall and reinstall the app to resolve common data issues.
Before installing the app, you might want to check the supported operating system for QBO for mobile devices. After that, please check this article for the instructions on how to install the app: How to download the QuickBooks Online mobile app.
I've also attached this article for additional reference: QuickBooks Online Login Verification Code.
For additional help, you can also reach out to our Phone Support. They can initiate a screen sharing session to help you get to the resolution quickly.
Please know that I'm just a post away if you should have any questions. Wishing you and your business continued success.