Hey Vincent! Good to see you around these parts!
Generally, hard to say what could be going on. If you said you had some issues earlier on, maybe the environment is in an inconsistent state - these scripts are really simple, they do not check much and expect that things will just be there that they require.
On the other hand, I have never had them hang indefinitely and usually the AWS CLI produces at least somewhat legible error messages. If you are trying to connect to the spot instance, did you first request it and did you see a message saying that the instance was spun up for you?
I think what could be really useful here would be logging into AWS Console (their web portal) and going to EC2 Dashboard. You need to go navigate to the region of interest and you will be able to see if there is any VPC already there, etc (VPC is the environment). More importantly, you will also be able to check the status of instances - if you have any running, etc. Also, under spot instance requests you will be able to check if maybe you have any pending requests - this is very useful as they contain a message which can point you to what the reason for the issues you are experiencing might be (incorrect config, something missing, too low spot price, etc).
The two scenarios that come to my mind where you could experience this hanging would be a) requesting an instance and setting too low of a spot price b) not authorizing your IP address to connect (the authorize-current-ip command)
Do take a look at the AWS console and see if anything would stand out. If you would have any further questions, you know where to find me