Looking at your selector, I don’t see anything terribly wrong. You could remove the idx, but it’s not going to fix it since the id is unique enough. Normally, I would suggest wildcarding the part with numbers in the id or looking for another attribute that’s more unique. If you use id, you could adjust it to
'*EndAfter*' or if you are afraid of case-sensitivity
but, like I said, your selector looks good enough in my opinion, so there is something else causing a problem.
Either the loading of the page was slower, and you need an adjustment to TimeoutMS… usually, the first element you interact with on the page should have a timeout of around 5000 or longer if loading is slow, and every element on the page right after should have a timeout of 0, since they should already be loaded at that point.
Or, the window size changed and it could not find the element for whatever reason. In this scenario, you could take a screenshot when the error occurs to see what the page looks like (TakeScreenshot activity and Save Image activity). If it’s a window size issue, try adding the Maximize Window activity in there, or if it’s a display size problem, then adjust the Robot settings in Orchestrator to run at the preferred HD resolution of 1920 by 1080, 32 bit depth.