Slow download and install failed error code IS-FC02

hello , since i downloaded epic games launcher i tried to download some contents (unreal engine 4.12.4).
the download speed was normal (about 250 kb/s ← my speed). how ever the problems is that it should have not taken so long with 250kb/s i should have downloaded this 3.3gb in 3 hours or so mean while it took like 8 hours for only 50%. it was ok till epic launcher stopped working and asked me to report the problem along with restarting it. i did do it. now it is trying to resume while failing with error code IS-FC02.
as in this pic :

this is not my first try to download ue4 , i did try it a long time ago (i think with the latest version of ue3 or the first version of ue4. (under win8 at the time).
for my os : win10
yes i have enough space (71 gb on current).
are you sure the ue launcher was using the net ? yes i check using task manager (not sure if this info is usable or even sure).
i’m on wifi , yes i’m only 2 meter away from the modem.
at the time of the download there was no internet usage , so there is no way to slow down the download.
i’m currently thinking about re-installing the ue4 launcher. re-starting my pc. and trying once more later on.
hope someone here will help me with a more logical answer and way.

update:
i tried closing unreal launcher. it took quite a long while. after restarting the problem with resuming the download is gone. however , the downloading has not changed for the longest time (1.4 gb left) with 180~250kb/s for 15 min.

update2:
the download is over and i managed to install without problem , but it still took way too long try checking this :

i hope that this was at least useful.

Hi .Night,

I’m sorry that you are having an issue with the Epic Games Launcher. In order for us to offer the best support, we have recently modified the process for how Epic Games can help troubleshoot your Launcher issue. Please visit http://help.epicgames.com/ for technical support, here you can find information and solutions for common issues, as well as a contact form if you still need additional assistance. To access the contact form, please use the “Email Us” button under the “Contact Us” section. Thanks!

Hi,

Please try the below steps :

  • Make sue you have admin privilege on the profile before you start installing
  • Disable the web filtering
  • Exit any anti-virus software before you start installing

If these steps doesn’t work, try to remove existing installation of the Epic Games software and start from the scratch following the above steps.