Accessing old tax returns & calculations

Hi, first time posting here. I'm trying to view my calculations for old tax years; 18-19, 17-18, 16-17 etc. When I try to look at them on the account it says "The filing window for the year selected has closed. Therefore you can no longer file a return for this year." I'm not trying to file anything, I just want to look at the figures.. What am I doing wrong? Thanks

Hi spinx101,
If you filed these returns online, log in to your personal tax account,  then select Self-Assessment within the Self-Assessment Tile.
From here, select 'View and manage your Self Assessment tax return’, then 'Get your SA302 tax calculation for tax year XXXX to XXXX. If you cannot see the required returns from here, contact us by webchat or phone here:
Self Assessment: general enquiries
And we can send the required calculations to you.
Thank you.