ERROR WITH NEW VexCode Blocks on Chromebook


Any help would be greatly appreciated. I have a group of teachers that keep getting this error on Chromebook devices when trying to download code to Robot Brain. Can’t access compiler server. Thanks in advance.

We just restarted the server a few minutes ago, but verified that everything is working on our end… are you still experiencing this issue?

Tried it this morning. Still not working.

Please send me a PM with your email and we’ll be in touch to help debug… there may be Chromebook restrictions preventing from reaching the compiler server.

Which Chromebook? Are you on a firewall, at school? Sure you are connected to internet? Check with your IT guy?


I’m getting the same message when I press the download button.

There’s three different potential issues that could occur on a Chromebook -

1. “No Internet Connection” - This error message would mean that the ChromeOS is reporting to VEXcode Blocks that it does not have a connection to the internet. This means either the Chromebook is not connected to the internet or VEXcode Blocks is being blocked by a system policy to prevent general Internet access. Behind the scenes, this check is querying “” to validate internet connectivity.

2. “Unable to access the compiler server”- This error message would mean theChromebook does have a valid internet connection (via ChromeOS system check + querying but is not able to talk to our AWS-based Cloud Compiler. The cloud compilers currently live here:

IQ Blocks - Cloud Compiler:
Host :
Port  :  5636

V5 Blocks - Cloud Compiler:
Host :
Port  :  5636

So most likely issue is a network blocking port 5636 and preventing the cloud compiler from receiving a response.

3. The “Brain” icon on the toolbar never turns green - This error the Chromebook does not see the VEX IQ Brain / V5 Brain. This usually mean either a system policy is blocking access to the Brain (via Chromebook management settings) or the USB cable is not fully plugged in.

VEXcode Blocks on Chromebooks requires an internet connection to only compile the project into “robot code” - otherwise the software is fully offline friendly for editing and saving projects. Using a cloud-based compiler is not the long-term plan for VEXcode - but more of an intermediate step to provide programming functionality on ChromeOS devices. The long-term plan is to develop an offline compiler similar to Windows/macOS for ChromeOS devices.

I’ll turn the above information into a article this week for easier searching as well. Hopefully this helps, but if not, please let us know.


I’m getting the same issue on iPad. It works from wired connection when on iMac or MacBook, but I get the error when trying to download program on iPad.

Same network in both cases. Seems to be a wireless problem with iPad.

Is this a personal Ipad? School Ipad? Do you have any firewalls? (School may have some hard coded into your Ipad).

Experiencing problems downloading code to brain from iPad. It says :
Unable to access compiler server. Please try again.

I’ve tried on our school network and hotspot from my iPhone to see if it was a network issue. No luck.

See this thread:

(You may also want to move this to category #vex-iq-general-discussion:vexcode-iq-blocks-technical-support)

Checked this morning and verified compiler server is running. After looking at the other thread related to networking issue, please let me know if you continue to run into this problem.