GL accounts are normally missing because they don't have an Account Number in a connected system, usually Quickbooks Online or Bill.com.
Add Account Numbers: The preferred method is to open QBO and edit the GL accounts in your Chart Of Accounts so that they have an account number.
Updates need to be made to each individual GL account in Quickbooks. (If you can't see the option for account number at all, you will have to turn this feature on first from "Accounts and Settings" and "Advanced", then return to your Chart Of Accounts and add the Account Number for each account).
If you're a Bill.com user:
Go to Bill.com
Add the account number(s) to the GL account(s)
Sync with Quickbooks.
Finally, click the Sync button at the bottom left of Vic.ai and your missing GL accounts should now be available.
If that did not help, do not hesitate to contact us for sync-related debugging!
Example: Bill.com chart of accounts with account numbers:
Where to add GL account numbers: