Thanks for replying; I genuinely appreciate it.  It is a physical product from one location (our shop), we never had the issues, but in the past several weeks, we got customer feedback they tried to order, but their address not recognised by Shopify....

We have an established Shopify store, tradig for seaveral years with no issues. Recently, we have had numerous customers writing to us stating that the delivery address is recognised, losing sales and creating frustration.  'We do not ship to this ad...