It was, as suggested above, that the email pipes needed cleaning. Normal service should now be restored.

If SkyDemon tells you the flightplan has been sent, then it has been sent. Of that you can be sure.

Agree, to se the FPL would be great. If one is not sure of what have been sendand the FPL maybe should be canceled and a new one send.

Same for me this weekend: Sat 29/10/16 and Sun 30/10/16.  I did get a GAR confirmation.
Both flightplans were for France, so a little concerned they might not arrive there, but they did!
Maybe some email pipes need cleaning.
One thing it did bring up, which is, that I could see the flightplan existed on my members page but the only options were to Cancel or Delay.  I didn't try either of these, but it would have been useful to be able to "display" the flightplan for further reassurance if this happens again or emails get delayed. Or is there anywhere else where the submitted plan is stored other than the normal email?

Same, for FPL sent at around same time as OP.

Hi,
I have sent to flight plans and both of them are visible if I login to the customer portal. But I haven't received emails with the plans (which I need to send to the customs). Any known issue with email sending?

Regards,
Per Welin