Hi there, cathy23.
Thank you for bringing your question forward here in the Community. I want to make sure you're able to work in your QuickBooks Online account without it crashing.
To rule out any browser related issues that could cause the site to shut down, I recommend clearing the cache first. The cache is used to collect frequently used data to make loading web pages quicker and easier. If the cache becomes too full it can cause certain viewing and performance errors within the system. Here's how to get this done if you're using Chrome for example:
1. At the top right, click More (three vertical dots).
2. Click More tools and then Clear browsing data.
3. At the top, choose a time range. To delete everything, select All time.
4. Check the boxes next to "Cookies and other site data" and "Cached images and files."
5. Click Clear data.
The following article provides similar steps for other browsers: Clear cache and cookies to fix issues when using QuickBooks Online
Please give this a try and let me know how it goes afterward. I'll be here if you have any other questions or concerns.