A recurring transaction in my accounts has all of a sudden gone out without GST charged and I can't work out why. Please help.

THanks for posting in the Community, felicity3!

If an item or GST code used within the recurring template is changed, the template should automatically be updated. However, there are times when an error occurs and the GST used needs to be re-saved on the actual template.

You can check the audit history of the invoice to verify if there were changes made on the invoice. Here's how:

1. Click on the Sales tab.
2. Locate and select the invoice affected.
3. Click on More at the bottom part, and click on Audit history.
4. On the next page, you'll see the details of the transaction.

In the meantime, you can edit the invoice created from the recurring template and apply the GST on them. 

If all else fails and it's unclear why the recurring template failed, first try to edit or recreate the problematic recurring template.

1. Click on the Gear icon and select Recurring Transactions.
2. Select the appropriate template and select Edit.
3. On the top left of the screen, you can edit the name of your recurring template.
4. Toggle the GST and change as needed.
5. Once all changes are in, select Save Template.

Changes to recurring templates are not retroactive. If you've got erroneous transactions that have been entered, you'll need to edit those just like any normal entry.

You can check this link to learn more about How to handle a recurring transaction that did not run.

If the issue persists, I'd recommend contacting our Customer Care Team. They have the tools to further check the template you're having issues with.

Post again in the Community if you need more help with QuickBooks Online. Have a great day!