Welcome aboard to the Community, @plantedterraria.
Since you're able to access your account through the mobile internet, I recommend checking with your ISP or consulting an IT guy. Your security settings may be affecting the connection with QuickBooks.
You can also configure the Firewall settings to ensure you can access the app without the system interfering. There are times you can't access an application due to the set up of the Wi-Fi or router.
For future reference about any sign-in issues, please visit the Get help if you can't sign in to your account article. It also provides some steps that will help you along the login process.
Please know the Community has your back. If you have additional questions, click the Reply button and post a comment. I’m here ready to assist further. Enjoy the rest of the day.