This rejection is usually caused when the share capital note has been edited and so is no longer correctly tagged for iXBRL.

To resolve this error you need to open the accounting period and click edit / revert to master format. You need to click deselect all to untick all items and then tick the line that references calledupsharecapital.htm and then click ok.

Once done rerun your accounts and then click through into tax and this should then allow you to file online to HMRC.