Issues connecting AI2 Companion with PC (/w Lightspeed Relay)

MIT App Inventor Help
#1

Good afternoon,

I am a support technician for my school district and am attempting to troubleshoot issues my users are having with AI2 companion.

The student users are working from local Windows 10 PCs and are 1:1 with Apple iPads. Both devices use Lightspeed Relay as a web content filter. The iPads are on a local network that can communicate with the PCs. When the students click Connect < AI Companion and input the corresponding code, they see no input from appinventor, no popup, and are unable to continue pairing the devices.

I have performed some testing and I will detail my results below:
Scenario 1. PC and iPad on same subnet. PC has Lightspeed Relay. PC's AI companion does not connect when iPad submits correct code, there is no feedback from AppInventor or the iPad's application. Packet captures from both devices simultaneously show TCP connectivity between each device and rendezvous.appinventor.mit.edu, however the handoff to the iPad's local address; X.X.X.X:8001/_proxy, never happens. Submitting the code from the iPad does seem to correctly open the 8001 port though, the PC can be manually connected to the iPad by typing it into an address bar of a browser. This doesn't do anything, but it shows there is connectivity there.

Scenario 2. PC and iPad on same subnet. PC has had Lightspeed relay removed. PC's AI companion option correctly connects to iPad when iPad submits correct code, and the project is displayed in the iPad. Upon hitting submit, a button that says "Continue" pops up, and a second window that points to the iPad's local IP address; X.X.X.X:8001/_proxy is opened and remains open. This is the desired outcome.

Additional facts:
PC Browser - Chrome 108.0.5359.125 (64-bit)
iPad MIT App Inventor Version - 2.64 (build 2)
iPad IOS Version: 15.5
Lightspeed has specific allowances for rendezvous.appinventor.mit.edu and both PC and iPad can visit this server on a browser. Packet capture for both devices doesn't seem to show any connectivity issues between the devices and rendezvous.

I recognize this is likely a Lightspeed Relay issue, but I unfortunately can't just remove it for the district. Does anybody have some experience getting this to work with Lightspeed Relay, or, is there anybody that can recommend additional testing that might shed some light on the connectivity process that Lightspeed may be getting in the middle of? It may not be Lightspeed, after all.

Thank you in advance

#3

Does the QR code window disappear? This sounds like it should be the case and then you end up with a progress bar dialog. At this point, the popup should open but doesn't based on your report. Are there any other extensions in the browser that might be used to block popups? Some teachers have reported GoGuardian preventing the popup window from opening. Do you see any error messages if you open the browser developer tool console?

#4

We do not push any extensions, and the PC in the testing lab does not have any enabled. The QR code section does not close when the correct code is entered into the iPad. The console output of the PC when the QR code is opened reads. I don't see anything when the code is entered on the iPad:

GET https://rendezvous.appinventor.mit.edu/rendezvous/ac84c47a1e1ec0096e623013e55e9227548aecc7 net::ERR_EMPTY_RESPONSE
TY.qb.ReplMgr.getFromRendezvous @ ode-0.js:6689
TY.qb.ReplMgr.startRepl @ ode-0.js:6689
ZX @ ode-0.js:3612
ZZ @ ode-0.js:6696
Wv @ ode-0.js:6042
dy @ ode-0.js:6693
bib @ ode-0.js:6697
d9c @ ode-0.js:6702
QYb @ ode-0.js:5595
GYb @ ode-0.js:4292
xYb @ ode-0.js:4049
wYb @ ode-0.js:5626
eval @ ode-0.js:3971

Great suggestion, I didn't think to check the output console.

Update: This morning my test machine isn't making it to Rendezvous at all, let me troubleshoot this.
Update2: Resolved this by clearing cache. The error output in console is still the same, but I have reconfirmed that I can still hit rendezvous

#5

net::ERR_EMPTY_RESPONSE suggests that something is still blocking or prematurely terminating the rendezvous server connection. The rendezvous payload you see in the Network tab should be a JSON payload that will contain the IP address for the iOS device, but the fact that you're getting a browser generated error suggests that there's an extension, firewall, etc. interfering.

#6

I need to check with our network administrator, but this may be cert related. While I am not entirely sure how/what Lightspeed is designed/configured to block, I do see that without a cert on rendezvous, I can communicate on port 80 but get an empty response on 443.

The redirect in the chrome console reads: GET https://rendezvous.appinventor.mit.edu/rendezvous/c545e581b6b3fd45d8e3972908a7ed0cc71f9b42 net::ERR_EMPTY_RESPONSE, indicating it is attempting a https connection which is failing for me.

#7

Alright, well, hilarious, but here is the solution.

https://help.lightspeedsystems.com/s/article/Filter-Agent-for-Windows-v2-3-1-RC-December-13-2022?language=en_US

Specifically this line:
Resolved an issue that caused ERR_EMPTY_RESPONSE to be shown on certain allowed websites

This was a Lightspeed Relay bug that had nothing to really do with MIT, other than luck/chance I guess. Deploying this release candidate on the test machine resolved the issue and allowed the device to connect to the iPad.

Hopefully somebody else with this specific subset of issues will find this useful!

1 Like
#8

Thanks. That's good to know.

#10

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