self assessment registration

I have a full time job and got some foreign bank interest income to declare. The HMRC system keep saying "we are unable to process your registration form for Self Assessment as the form is incomplete". I think it is due to none boxes for the reason of the need to complete a return was checked. As my foreign interest income is less than £300, so I did not check the box. Could you please advise how can I register for self assessment then? Thank you so much.

Dear HMRC Online Team, I have a question regarding starting a business and registering as a sole trader in the UK, and I hope you can provide some insights on the matter. If I start working tomorrow as self-employed (in a computer job), are there any specific rules regarding when I should register for self-assessment and as a sole trader? Or should I proceed immediately after starting working as self-employed and earning my first income? Thanks for your assistance

Hi nicoleuk,

If there is a box asking for any other reason why a return is required you can fill in that box.

Thank you.

Hi LeriJam,

You can register straight away or register at a later date.
You may not need to register if your income will be below £1,000 in the tax year.
Tax-free allowances on property and trading income Self-employed

Thank you.