Error message 1608 'Unable to lookup taxpayer details' comes from HMRC. 1608 indicates that HMRC are unable to process their checks required to pass the entered UTR.
This could mean that the UTR:
- has been incorrectly entered on the return OR
- has been disabled on the Gateway after dissolving at Companies House OR
- is for another HMRC service (this can be checked against HMRC paperwork received)
You will need to contact HMRC to ensure that the UTR entered is correct and to advise how to proceed.
Below is the extract from HMRC's online document:
The HMRC contact details are available on this link.