Hello there, amyh3,
Merging helps organize and keep track of your finances by consolidating transactions and removing duplicate accounts.
Those 2 GL accounts have different account types, and that's why you're getting an error when merging them. Make sure to change their types so you can the other one as a sub-account. See the attached screenshot below for your visual guide.
If you're getting the same error, it could be a browser-related issue. You'll want to perform the recommended steps to help fix and isolate this behavior. You can start by clearing the cache and cookies depending on your browser.
Follow the linked steps for your browser:
After clearing the cache, make sure to restart your browser for changes to take effect. Then, log in to your QuickBooks account and merge them again.
I've added these articles for additional information with the given data above:
Stay in touch if there's anything else you need by clicking the Reply button. I'm always around to help.