Lighting will not build offline

Development Platform & Builds
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1

Hello, I have an interesting problem. The lighting refuses to build offline. (I’m using Ubuntu guys. No swarm here.) But it builds online perfectly fine. Why is this happening?! Also, I have turned the firewall completely off! Help would be appreciated!

2

Hey 94-

I just want to confirm your meaning of offline vs. online. Are you simply referring to if the computer has an internet connection or are you referring to something else? Are you able to build light in a new project when offline/online? What error do you receive when trying to build lighting offline?

3

Try unplugging the cord before starting the editor.

4

Thanks for getting to my question so quickly!
About the offline thing. I physically unplug the cord. No internet whatsoevr.
Also, there is no error. It just stays on 0% forever. (Counted 10hours for FPS template. gave up and went to bed.

5

Sorry for the typos. It’s hard to type while eating a sandwich…

6

And I should probably explain more… (Man I suck right now.)
When I am connected to the internet it builds fine. But when I unplug it, it refuses to build the lighting. Just stays on 0% forever…

And yes, I try to open different projects. Even restart the editor and computer. Nothing… (Sorry for the weird amount of posts… I’m a little scatter brained right now!)

7

I have tried that.

8

Bumping this up… Still having this problem…

9

Hey 94-

I was able to reproduce this after unplugging the ethernet cable from the computer and have entered a bug (UE-18201) for investigation. For now you will want to continue building while connected to the internet.

Cheers

10

Thank you for your guys help!
And thanks for putting it under investigation.
Hopefully it will be solved soon!
Just hope my internet doesn’t go weird on me!

11

Still not fixed in 4.18.1

12

Could you try enabling multicast on the loopback like this:

sudo route add -net 224.0.0.0 netmask 240.0.0.0 dev lo
sudo ifconfig lo multicast

and retrying after that?

13

I am experiencing this issue still in UE 4.20.1 on macOS. As soon as I try to build lighting I get an error message:

Failed to connect to Swarm. Check that your network interface supports multicast.

I tried the route and ifconfig commands above but I’m pretty sure they are Linux specific as I get errors.

$ sudo route add -net 224.0.0.0 netmask 240.0.0.0 dev lo
route: bad address: netmask
$ sudo ifconfig lo multicast
ifconfig: interface lo does not exist
14

I’m using UE 4.19.2 on an offline Mac running macOS 10.12.6 and had the same problem with the above staff-provided Unix commands not working. So I looked some stuff up and translated those commands into macOS terminal speak. Try entering it this way instead:

sudo route -nv add -net 224.0.0.0 -netmask 240.0.0.0 -interface lo0

I didn’t seem to need the second line – just the first one. This worked for me, as I’m no longer getting the ‘Failed to connect to swarm’ error. Good luck!

15

Thanks for the translation. I’m no longer getting the “failed to connect to swarm” error, but now lighting building sits at 0% for a couple minutes and fails with “LogHttp: Warning: didFailWithError. Http request failed - The Internet connection appears to be offline. https://datarouter.ol.epicgames.com/datarouter/api/v1/public/data?SessionID={68F92E51-F64B-2F44-F6DA-F486EEB78357}&AppID=UEEditor.Rocket.Release&AppVersion=4.20.1-4233996%2B%2B%2BUE4%2BRelease-4.20&UserID=ac518089cb4a549fd3758cabf75cab79|e8286e1dbde
6418a90845c7821a3e4ad%7C6FD4F32E-6116-5D5A-8A3D-2D60DD90602C&AppEnvironment=datacollector-binary&UploadType=eteventstream: 0x60c00025f9b0”

16

I have the same problem. Did you ever resolve the issue?