When I reconcile the GL, I see the difference is not 0 and clicking the details, it state the list of transaction but the last change is "Invalid date". Please help me.

I can help you fix your reconciliation issue, HONG1.

When working in QuickBooks Online, you'll encounter an Invalid date warning if you're attempting to reconcile a wrong transaction in the Chart of accounts.

If you've accidentally deleted a transaction and prevented you from reconciling the account, you can recreate the deleted entry by referring to the details in the Audit Log. Here's the process:

1. Go to the Gear icon, and select Audit Log.
2. From the Filter dropdown, decide the correct user, date, and events and look for the deleted transactions.
3. On the History column, select View.
4. Re-create the transactions based on the details in the Audit Log.
5. If done, change the reconciliation status in the register to "R" for the Reconciled.

Once you've recreated the deleted transaction, you can properly reconcile them in your QuickBooks accounts.

For more troubleshooting guidance on handling issues related to reconciliations in QuickBooks Online, refer to this link: Undo or remove transactions from reconciliations in QuickBooks Online.

Moreover, you can check this article to learn what to do if QuickBooks Online doesn't match your bank statement at the end of a reconciliation: Fix issues at the end of a reconciliation in QuickBooks Online.

I'll be around if you need further assistance with reconciling your account.