You need to make sure you are url-encoding all of your API parameters if you are passing them in the URL. Most of them won’t really change but the test URL and script can often have characters that MUST be encoded.
Mostly likely that’s the issue for the OP, that being said, for me this error is being thrown if script starts with anything else than ‘navigate’, e.g.
I get the OP`s error if I start my script with logData, it works however if I start with navigate.
Still playing around as I get the job accepted but it looks that script part of logging in does not work, just the first line of navigate aka going to right URL to start with.