{"type":"error.SuiteScriptError","name":"SSS_REQUEST_TIME_EXCEEDED","message":"The host you are trying to connect to has exceeded the maximum allowed response time."

Does this error happen sometimes because it is the first time to hit that endpoint in a few hours? Like it is warming up?

Not usually, no. Unless your script is doing something to warm up like loading a cache or something. Searches are cached by Netsuite in the backend so bear that in mind.

I have a SuiteLet that does this on sandbox, usually first time I open it in the day. But not every time I open it.

Since a couple weeks ago I've gotten that error too. Not sure what's up. It's happened on multiple different scripts hitting different end points and it's pretty random

Thanks very much for commenting... I couldn't find the reason and thought that I am doing something wrong, while it works on other accounts just fine.