Opening Asset Numbering Issues

As per clients requirement automatic asset numbering is to be used for fixed assets but in opening data few assets are disposed and those will not be loaded into opening data/assets so there will be gap in Asset numbering.

In UAT server i have configured FA and in system controls i have assigned auto asset numbering from 1.

I tried to load assets through WebADI by assigning manual asset numbering but getting the below mentioned error.

"The Asset Number entered is invalid because Manual Asset Numbering is disabled. Action: Re-enable Manual Asset Numbering or clear the Asset Number value and Automatic Asset Numbering will create the Asset Number"