Worked fine for me. I filed a flight plan with a departure time a couple of hours in advance of now, and then got a briefing.
Then I found a bug: I cancelled the flight plan from earlier, then tried to file a flight plan with a departure date in January 2021 (per your posted error message), in case that's what you inadvertently did. But it won't let me -- when I click on Options (to get to the File Flight Plan option) it pops up a dialog box asking me if I want to "cancel this flight plan online?". Which I OK, and then it gives me an error message about cancelling it (since Leidos doesn't have an active plan). It doesn't matter if I clear the flight plan and load a different one. It just won't let you file.
I exited iFly and restarted. It STILL won't let me file ANY flight plan. Great. How to clear this? I went to C:\_iFlyGPS_Data\User\#FiledPlans to see if some persistent flight plan(s) is in there. Nope.
Ahh, so I stopped trying to file these flight plans with a January 2021 departure date (letting it default to today). Voy-lah, it will now let me file. So the misleading error dialogs occur if you set up a flight plan with a DATE in the past. That whole confusion, with faulty dialogs, should be "headed off at the pass" by simply error-checking the user's departure date to prevent them from entering something in the past. BTW: it does correctly error-check you entering a TIME for today that's already passed.
I'm running version 11.1.1
OK, so it doesn't seem that you put the wrong date in your flight plan. I figured you didn't, since the image you posted had a line in it that said the departure date was today. But I thought I'd see if that line was giving incorrect info, since your error message says the departure date is 1/20/2021. I also tried setting my PC date to a week ago, and then doing a filing+briefing. (It worked fine.)
Which version of iFly are you running? Just for grins: is the date set correctly on your PC?. Is there anything weird about the date/time in your flight plan? Did it file OK?