I get this message when trying to manually update detailed data from a run using the classic interface. "Your "Start" value is not within permissible limits." The problem lies in the panel not accepting today's date (at 2:00PM GMT). Setting yesterday's date clears the error. Going into the detailed manual entry panel from the modern interface worked (or it could be I did that a few minutes later and the server clock had been corrected?) Both the modern and classic detailed manual entry panels look the same, so the different results are a puzzle.
This problem has been reported before, with the same symptoms. (Google the error message).