Can't fill in my Return

I've only made around 3k this tax year, but everytime I try and fill it into my Self Assessment it says that I need to please complete 'Date your books or accounts start on the previous page'. Problem with this is, is that it's optional. I've filled it in but it still seems to have not worked. I don't know what to do and it's really messing up my mental health.

Hi

Try logging out of your return, and filling it in again from the beginning, this time entering the appropriate date in the box when you first see it.
If doing this does not resolve the issue, contact us by webchat or phone via Self Assessment: general enquiries, and we can provide further assistance.

Thank you