It's great that you've already corrected the data using the HMRC's Basic PAYE Tool, creationoutdoors. The File outside of QuickBooks error occurs because QuickBooks Online is not yet capable of filing Earlier Year Update report.
Since you mentioned that the affected period was around 5 months ago which was last year, we are suggested to file another FPS with the correct year to date figures. Check this link for more details about it: Fix problems with running payroll.
The submission of another Full Payment Summary (FPS) will override the Employer Payment Summary (EPS) on record with HMRC. The steps may vary depending on your subscription with us:
After submitting the updated FPS, we can already resubmit the corrected EPS to HMRC. Though the process I've mentioned above can easily be done by you, I'd still recommend reaching out to your payroll advisors or accountant. They know exactly what to do now and in the future.
Then, we can already view your HMRC Online within 2 days (or by the 14th if you sent the EPS before the 11th). Lastly, you can pay HMRC by the 22nd (or the 19th if paying by post).
We'll be right here if you have further queries regarding the FPS and EPS correction process.
