SA Form: Self Employed losses problem

[Steve2H]

Hello,
I am trying to complete my online self-assessment form and cannot get past the Losses page for self-employment, due to persistent error.
The business has made modest losses on the last 5 years.
On the losses page I am getting for the “Loss to be carried back to previous year(s) and set-off against income (or capital gains): (optional)” an error message “The amount entered for 'Loss to be carried back to previous year(s) and set-off against income (or capital gains)' must be greater than 0 (zero) or blank. Please amend.” – no matter what is entered in the other boxes (including 0s).
If a non-zero amount is entered in this box then the error is “The amount entered for 'Loss to be carried back to previous year(s) and set-off against income (or capital gains)' cannot exceed the positive equivalent of 'Net business loss for tax purposes' minus 'Loss from this tax year set-off against other income for 2023-24'. Please amend.”
I do want to carry back any loss to previous years.

No matter what I enter in “Loss for this year set-off against other income” or “ Total loss to carry forward after all” there is always one of these errors for the “Loss to be carried back to previous year(s)” entry. And I cannot proceed.
I am using accrual basis so if possible, I can use sideways relief on other income (property and paid employment), although in previous years was using cash accounting.
Can anyone shed any light on this?
Thank you