Spreadsheet help

I have made this spreadsheet but it only works sometimes.
Most days I open it I get this:


Sometimes it loads and I can see the prices & Qty.

what I use: =importxml(CONCATENATE(“https://api.evemarketer.com/ec/marketstat?usesystem=30002187",“&typeid=”&JOIN("&typeid=”,$B3:B10)), “//sell/min”)

Can anyone help me fix this problem please.


https://i.imgur.com/chbeM59.png there must be no empty cells