Your CT600 cannot be submitted because your company's accounting period has not yet ended. HMRC requires the accounting period to be fully complete before a corporation tax return can be filed, as the return must capture the total trading activity for that period.

The same applies to your annual accounts submission to Companies House - these also cannot be filed until the accounting period has ended, as they must reflect the full and accurate financial position of the company for that period.

Once your accounting period has ended, you will be able to prepare your filings and submit these through our software to both HMRC and Companies House. It is worth noting that whilst these two submissions are linked, they have separate deadlines - you have up to 9 months after your accounting period end date to file your accounts with Companies House, and up to 12 months to file your CT600 with HMRC.