Error when running script

[JN8086]

I want to use the script to extend the developer mode timeout. I've copy-pasted it from the dev manager app and have it running from a server on my local network. When I run it, this is the output I get:

Script location: /tmp/user.scripts/tmpScripts/Extend Developer Mode Session LG TV/script
Note that closing this window will abort the execution of this script
Your identification has been saved with the new passphrase.
Got SESSION_TOKEN from TV - writing to /tmp/webos_devmode_token_LG TV.txt
{"result":"success","errorCode":"200","errorMsg":"GNL"}

What am I doing wrong?