Error message
In the message, %s marks a value that the engine fills in when it raises the error.
The story
This is a refusal about patience. You wrote a call that can wait on the outside, such as an http request, a websocket, or next request on a server, and you did not say how long it may wait. The engine will not guess. Think about it: how long should a program wait for a stranger on the internet? Ten seconds? A minute? A day? Only you know, because it depends on what your program is for. So the engine owns no default and no secret number, and it stops at parse, before anything runs. The fix is one small link right after the call. Write dot timeout, bracket, ten, and the call gives up after ten seconds and answers no answer, with its outcome unknown. Or write dot timeout, bracket, forever, and you declare that you will wait as long as the peer takes, with confidence, because that is your intention. The word is forever, not none, since none already means do not wait at all. Say how long, and the call runs.
Text from the Rush engine's error catalogue.