Can you please advise the country code for UK? I got an error, why is that?

When importing an Informal Supplier, please check out this article, Country Code list

for a full list of Country Codes.

The two-digit code for each country must be used to satisfy the compulsory naming conventions for all new Informal Supplier setups.

The following help guides will also be useful, Import multiple Informal Suppliers,

Informal Supplier Import Template.csv.