Why do I get a red restricted banner when I try to buy a cable?

[3dex_94]

I tried to purchase a power cable from a well known supplier and a red banner popped up saying this is stricted, find an item to pay in person!

Although I don't buy much on eBay I have never seen this before. 

How do I make a normal purchase?

[twyngwyn]

what is the item number?