In addition to some of the recommendations below, above, the solution to this is by:

1. Before anything, ensure that your AWS account has allowable vCPUs > 36 cores to take full potential of PAT's available AMIs. You can easily request an increase from AWS and you'll get a response within 2 hours.
2. Setting up a completely new PAT project (don't copy PAT folders or save-as)
3. Entering AWS cluster settings.
4. Attempting to connect to AWS. You will notice that this attempt will fail, it's okay.
5. Save PAT (never force close), close after saving, and then reopen your PAT project
6. Attempt a connection again to AWS; this will highly likely to succeed.

In addition to some of the recommendations above, below, the solution to this is by:

1. Before anything, ensure that your AWS account has allowable vCPUs > 36 cores to take full potential of PAT's available AMIs. You can easily request an increase from AWS and you'll get a response within 2 hours.
2. Setting up a completely new PAT project (don't copy PAT folders or save-as)
3. Entering AWS cluster settings.
4. Attempting to connect to AWS. You will notice that this attempt will fail, it's okay.
5. Save PAT (never force close), close after saving, and then reopen your PAT project
6. Attempt a connection again to AWS; this will highly likely to succeed.