I'm here to ensure you're able to access the "Help" references and post a question from our Intuit Developer Forum, @MGH1. 

Accessing the "Help" articles within our developer site doesn't require an account login. However, posting a question from there needs a complete setup for your Intuit credentials. The screenshot below serves as your visual guide. Since you're experiencing an endless loop of "Sign in" pages, the browser's stored cache may be full. I'm also unable to confirm if there must be some test that only developers can decipher, but I've got the steps to help resolve this. 

I'd suggest opening the developer site using an incognito window. It doesn't store data in the cache, so this is a great way to help fix the issue. Here are the keyboard shortcuts: 

• Mozilla Firefox or Microsoft Edge: CTRL + Shift + P 
• Google Chrome: CTRL + Shift + N
• Safari: Command + Shift + N

Once opened, go back to the "Help" articles or click the Ask a question button. If this works, let's clear your main browser's cache, so it'll function efficiently. Otherwise, you can use a different browser to get the best and most secure experience with the program. 

When your customer accepts the estimate, you can convert it into an invoice. Once done, the system will auto-reflect its status as Closed in QuickBooks Online (QBO). 

Just click the Reply button below if there's anything else you need. The Community and I will help you.