Remsh Cookie Format: Connection attempt from disallowed node

I’m trying to connect to a remote node but the request keeps getting rejected. The error is: “Connection attempt from disallowed node”. I understand this means the cookie is invalid, i.e. doesn’t match the running node.

When I SSH to the remote machine and run cat vm.args I see:

## Name of the node
-name myapp@127.0.0.1

## Cookie for distributed erlang
-setcookie JGpXR9PPNYgMLhMii#3VktVMUAb7dRU3G3VdLsLYXk6t

When I start a session on the remote machine, this cookie shows up as:

$: iex sname will --cookie JGpXR9PPNYgMLhMii#3VktVMUAb7dRU3G3VdLsLYXk6t
Interactive Elixir (1.5.1) - press Ctrl+C to exit (type h() ENTER for help)
iex(will@iex_test)1> :erlang.get_cookie()
:"JGpXR9PPNYgMLhMii#3VktVMUAb7dRU3G3VdLsLYXk6t"

No matter how I tried to represent the cookie I get this error: {cookie}, '{cookie}', "{cookie}", :"{cookie}".

I’m deploying the application inside a Docker container. My cookie is exported as an environment variable and I’m wondering if it’s getting set in a different format when grabbed by System.get_env("COOKIE") in the Docker container than when it’s set from the shell.