Do you have any other shares? Double check logging in with them...

Do you have any other shares? Double check logging in with them on computer share, link market services or similar share registry etc.

If they don’t work then it’s definitely the details. the HIN should have the X and 0’s usually up to 10 digits (but can be 11)

also check the postcode. I know lots of people either move or have a different postcode setup when they first registered/bought shares and never update with the registry. It should be the same postcode shown on any recent mail you may have received from the company.