[torrentcore] (testing) Exception (torrentcore): Error: Connection failed: Connection refused: Parse error about jackett HOT 2 CLOSED

The anti-DDoS message is generated by the web site. Despite Jackett having a 10.1 second request delay between any searches you make, via either the Jackett dashboard or via a Torznab query (such as from any of the *arr apps for example), the site still generates this error intermittently, and there is nothing Jackett can do about it.
Generally, after getting this message, I try the query again and the search returns results most of the time.
It's not worth out time and effort to rewrite the indexer from yaml to C# in order to try to handle the anti-ddos block from the site and retry the query after yet another 10.1 seconds.
IMO there are other public indexers to choose from that have the same content and dont have resource constraints as torrentcore apparently suffers from.

from jackett.

Also, the site occasionally stops presenting the home page with the latest results

when this happens the Jackett TEST button (or a keywordless search) stops returning results which is another problem that cannot be solved.
Basically this site is not in good shape ATM.

from jackett.