How to file the first self assessment form online even the online tax account has created?

I created the online tax account with and reported no employment to HMRC one month earlier. I were then advised no tax to be paid. However, I tried to submit self assessment form via the online tax account and were unable to do such submission via the account. Please advise how to proceed.

Hi,
You would need to contact HMRC to check if you are registered for Self Assessment:
Self Assessment: general enquiries
Thank you.