Orchestrator on AWS with ALB


I’m installing UI Path platform on AWS. I have an ALB in front of the orchestrator.
When trying the connect the robot to the orchestrator going through the ALB I get the following error :
The requested resource cannot be does not support http over method GET.
It seems its because the method length accepted on the ALB is 127 char max.
Anyone have the same issue ?


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Hi Maxime,

I did not this error, but i face the following error: An error occurred while sending the request.
Can i check with you, does your Orchestrator instance using https / http ?

Does your ALB stores the SSL certificate and it using https protocol communicating to the internet, and http protocol within the VPC?

Hi Marc,

I’m using both HTTP and HTTPS on Orchestrator but it seems that robots only connect to the Orchestrator over HTTP.
Yes ALB (from AWS) stores SSL, we usually use only HTTPS within VPC. But in this case we deploy a special ALB only for robots, so robots and users connecting to the Orchestrator use a different URL to connect to the same target.
Hope it’s clear.


May you share more with me on the special ALB?
May i also conclude that you are using two alb for 2 purpose? 1 is for the users to access and web api. The other alb is using for just robot communication with orchestrator

Is you architecture strcuture live now?.

Yes 2 ELBs,

  • 1 ALB (type:application) for users to connect to the Orchestrator, it redirects the traffic to HTTPS
  • 1 ELB for robots that leave traffic on HTTP

Yes we are live and it’s working well on the network side.

I setup UiPath on AWS a few months back, by default the Robots communicate with Orchestrator over HTTPS, did you switch to using HTTP for a particular issue you were running into?

I originally had a NLB in front of our Orchestrator but took it out due to other issues I was having with Route53 and the NLB. In regards to the Robots and HTTPS the only thing I had to ensure was the robots trusted the certificate that was being served by Orchestrator.

Hi twhitehead, what type of licence you have with AWS to setup UiPath?
3 servers AWS A1xlarge ?

  • 1 for web application
  • 1 for sql server
  • 1 for the vm and unattended robot

Hi @Foulques_de_Valbray,

Currently, we have three AWS environments (Dev, Pre, Prod).

  • Dev is where I test infrastructure setups.
  • Pre is where we develop our automations
  • Prd is our production environment

Dev is changing all the time, but for the other two currently

  • 1 EC2 instance (t2.xlarge) for Orchestrator
  • Use RDS (db.m4.xlarge) in Multi-Az mode for our SQL Server SE
  • 1 EC2 instance (t2.xlarge) per unattended robot

Some point in the future I plan on putting the NLB/ALB back in and adding some more Orchestrator instance.