Error: 14 UNAVAILABLE: Name resolution failed for target dns:testnet-gateway.presearch.org:2017

This means your node can’t connect to the Presearch gateways through the internet.

The issue is on your end not Presearch.

Usually this will be due to one of the following:
1) your internet being down or unstable,
2) your ISP’s DNS servers being down or unstable
3) you being connected to a VPN that is down or unstable, or
4) your system having Docker configured in a way that your node can’t access the internet.
5) you having a firewall configured that is preventing your node from reaching the internet

If you can NEVER connect, then #4 or #5 seems likely. If you can usually connect but get this sometimes, it’s most likely #1, #2, or #3

Try using an alternate DNS provider. Here are 2 big ones:

Google DNS
Preferred: 8.8.8.8
Alternate: 8.8.4.4

OpenDNS
Preferred: 208.67.222.222
Alternate: 208.67.220.220