Printing postage error message

[Jackie621]

I keep getting this massage when trying to print label :Unable to print the requested postage label at this time. The following error occurred.

The dimensions entered are not supported for the package of your choice, please correct the dimensions to proceed. What does it mean

[Hutchys]

Exactly the same issue with any labels i try to purchase.

Started with small parcels 2nd class not working. 

Now even first class, signed for and large letter dimensions are coming up with the error.