Happy to help, @Sparky123.
To better assist you, can I ask for more information about what isn't being transferred? Are you attempting to convert QuickBooks Desktop or any other 3rd party data to QuickBooks Online?
While I wait for your response, you can read the following articles about transferring data to QuickBooks Online and other related matters:
Simply click the Reply button to the right to add your response. I'll await your response so that I can resolve this issue as soon as possible. Keep yourself safe!
