Hi homeaccounting-e,
Welcome to Community! When the sales tax isn't registering on your tax return, I can see how it would be rather alarming. QuickBooks Online calculates line 101 based on your total sales for the return. I'd be happy to provide more insight here!
To resolve the missing sales tax, I suggest looking at the Transactions without Sales Tax report, by selecting Reports from the left navigation menu. Enter the appropriate Report period and the Accounting method, then proceed to Customize the report as you see necessary. If you've created journal entries, they'll also appear on the report. Please note that the sales tax on journal entries must be added to a line item, rather than entered on a separate line, in order for it to be tracked in QuickBooks Online.
Should you require additional assistance, please don't hesitate to contact us outside of Community. We'd love the opportunity to work with you directly and ensure you're able to accomplish your QuickBooks goals as soon as possible!
Schedule a Callback or start a Chat: click (?) Help in the upper right in QuickBooks Online > enter "Contact support" > hit Contact Us > provide a brief summary of your situation > hit Let's Talk > choose Get a callback or Start a Chat.
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