To provide better assistance, I'd like to ask for additional details. Does the crashing occur when you try to access your account or perform a specific function?
Most of the time, problems associated with accessing QuickBooks Online (QBO) has something to do with the browser version. For this, I recommend ensuring your browser is up-to-date. Here's a list of supported browsers:
Internet Explorer is no longer a supported browser.
Google Chrome: version 78 or newer
Mozilla Firefox: version 76 or newer.
Microsoft Edge: version 79 or newer
Safari: version 12 or newer (Mac only)
Opera: version 68 or newer
Samsung: version 10 or newer
Next, after ensuring that your browser is up-to-date and the crashing persists, I suggest accessing your QBO account through your browser's incognito mode, as this can be also a cache-related issue. Here's how:
Google Chrome: Press "Ctrl + Shift + N"
Mozilla Firefox: Press "Ctrl + Shift + P"
Microsoft Edge: Press "Ctrl + Shift + N"
Safari: Press "⌘ + Shift + N"
When this works, please proceed to clear your browser's cache. Doing so will remove and fix any problems and optimize the program's performance.
Let me add this resource should you have other QBO-related concerns: Self-help articles.
We're always here in the Community should you have further updates on the crashing issue you've encountered. We'll do our best to assist. Take care.