RSS feed stopped working after 7 years

[JohnnieOO]

Hello all,
I have a vB3 site that I was importing RSS feed from Craigslist. This past July it quit working and I cannot seem to make it feed. I've tried placing the URL directly copied from the address line (when the Craigslist RSS page is shown) and I have tried copying the link given ON the RSS page. They have slightly different syntax.

The line of code on the RSS page is here :
<channel rdf:about="https://appleton.craigslist.org/search/sss?format=rss&query=camping%20tents%20stove&sort= rel">

I have entered everything in between the ""s and get this error :
XML Error: Not well-formed (invalid token) at Line 2

Any thoughts on what I need to do to get this working again? It worked flawlessly for 7 years.

Johnnie