Trying to submit Apr '21 to '22: "You cannot use this service."

Hello, any help on the below appreciated please. I want to submit my self-assessment tax return for financial year 6 Apr 2021 to 5 April 2022, during which I was self-employed. Problem: I get the error "You cannot use this service." in the box next to Apr 21 to Apr 22 at https://www.tax.service.gov.uk/tax-you-paid/choose-year. So I can't submit my return. Details: The previous year (20-21) I was employed and the system tells me I submitted the right amount of tax. In order to access 21-22 I click 'Choose which year to view' at the top. For 21-22 I get this error saying I can't use this service. I registered as self-employed in August 2022, was this too late? Even though the deadline for the return is 31 Jan 2023? Any guidance appreciated. Thanks, 

Hi,

You will need to contact the self assessment team:

Self Assessment: general enquiries

to check whether a return request has been issued.
 
If self assessment is not expecting a tax return, it won't allow you to submit one online.

Thank you.