The submission includes a Group identifier that doesn't match what the pension provider is expecting. The Group identifier is the name given to a subset of the pension scheme - sometimes called a group name or category. Please ensure that the correct details have been entered for the scheme in payroll. Please note that if a user has recently added the Group on your pension provider's portal, it may need to update overnight before you can submit this data.
The issue appears to be the Group/payment Source that you have set up in payroll, isn't the same as what you have at NEST. The course of action is:
In payroll, go to the Payroll Settings > Pension Settings and and select to 'Import from PensionSync' from the Action button and follow the steps for your NEST scheme.
After a minute or two, this populates the Contribution Plan section at the bottom of the same screen with the Group details from NEST (should be called 'Monthly Plan' or similar). Check through these, including setting the right collection source (NEST payment source) with the Plan, and ensure you save the screen when you're finished.
You need to ensure your employees for NEST are linked to the correct Contribution Plan (NEST Group), so for each employee on the employee's Pension Settings, select the correct Contribution Plan (Monthly Plan) and save the screen.
*NB* We sync at least once every period with NEST as the Groups don't tend to change that often. But we can sync for you at any time, just open up a new chat or email firstname.lastname@example.org so we can update your new or edited Group on our system too.
Once done, resubmit on the payrun screen.