Unable to shell from Rancher 'dashboard' (Disconnected)

I’ve recently deployed Rancher 2.4.5 using the Helm chart on to a EKS cluster (1.15), behind a L7 AWS ALB. It uses the nginx ingress with the following configuration:

location / {
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection “upgrade”;
proxy_connect_timeout 60s;
proxy_read_timeout 900s;
proxy_send_timeout 60s;
client_max_body_size 1m;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-Port $server_port;
proxy_set_header X-Forwarded-Proto https;
proxy_buffering off;
proxy_pass http://cattle-system-rancher-rancher.XXX-80;

I’m able to access the Rancher UI using https, and I’m able to Execute Shell and View Logs when accessing a particular pod - all from the standard UI. However, when I attempt to Execute Shell from the ‘dashboard’ UI (domain.com/dashboard), I immediately receive a Disconnected notice in the bottom right corner of the screen. I am able to view logs using the Dashboard however.
This is consistent across both Firefox and Chrome.

I’ve checked the following pods for errors:

  • Rancher pod
  • cattle-cluster-agent

but no luck. Has anyone else experienced this problem? Any suggestions on where else I should be looking for errors?