I have a chart running in realtime mode with about 6 tags being displayed. At random I get an error saying that the end time is greater than the start time. I think it only randomly happens in designer. I’ll post it when it randomly pops up again.
Do you have the start date and end date backwards?
Also, what version of Ignition are you using? I think I recall something like this being fixed around 7.4, but I can look up more specifically if necessary.