Thanks for reaching out to us here in the Community. I'm here to share some information about retrieving the Journal Entry that you've created in QuickBooks Online (QBO).
Did you get an error message when you tried to save your Journal Entry? If so, may I know what specific message you receive?
QBO has an Audit Log feature that maintains a log of each financial transaction as it is added, changed, or deleted. This will also serve as an audit trail that lets you see what changes were made, and who made them. However, you may only see these transactions once you saved them.
In this case, you'll need to recreate the Journal Entry since QBO doesn't have the option to retrieve it since you're unable to save it. Before doing so, try recreating it using a different or a private browser. There are times that the browser is full of frequently-accessed page resources, thus causing some errors and/or unusual responses.
To use a private browser, here's how:
On your keyboard, press Ctrl + Shift + N (Google Chrome).
Ctrl + Shift + P (Firefox or Internet Explorer).
Control + Option + P (Safari).
If it'll work, go back to your default browser and perform clear cache to remove temporary internet files on your computer. Before doing so, make sure to take note your saved passwords and URLs. Once done, here's a helpful article with the steps on how to perform clear cache: How do I clear my browser cache and temporary Internet files?
Give this a try and let me know how it goes by leaving a comment below. Please know that I'm only a post away if you have any follow-up questions. Looking forward to your response and providing further help. Have a great rest of the week.