Self Assessment Online Account for Someone Without A UK Post Code & National Insurance Number

I am helping my husband make a Self Assessment Online Account. He is an American Citizen with a rental property in the UK. We need a Self Assessment Online Account so that we can link it to TaxCalc to submit our Self Assessments online. We cannot submit directly through the HMRC online account as we are living in the US. We are Non-Resident Landlords. The TaxCalc software allows us to submit online when linked to an HMRC Self Assessment Online (Individual) Account. When making the account, my husband must verify his identity by entering a UK postcode associated with his HMRC returns. Last year's return was associated with our US address, so how can we enter a UK postcode? We tried entering our postcode from when we lived in the UK (2018-21), but that didn't work either. Please help! P.S., in case it matters, my husband does not have a national insurance number.

Hi faye_angharad,
Without a UK address, you may be unable to file online, with a paper return required instead.
For more advice, please contact out Online Helpdesk by webchat or phone here:
Technical support with HMRC online services
Thank you.