Invalid requester VAT number

Hi,

I see the following error. How do I resolve, please? Thank you

EU VAT Assistant – Settings (v. 1.13.2.200319)
Invalid requester VAT number entered in section Options > VIES Validation. The new requester VAT number has NOT been saved, because it would cause the VAT validation to fail at checkout.

Selected VAT Country: “United Kingdom (UK)”. Entered VAT Number: “[Correct VAT number with no letters]”. Raw validation response (JSON):

{
“euva_validation_result”: “non-eu”
}