ipcluster won't start in a certain directory

There is one directory where when I try to start ipcluster, I get the following:
>ipcluster start
2021-04-23 10:06:33.597 [IPClusterStart] Starting ipcluster with [daemon=False]
2021-04-23 10:06:33.597 [IPClusterStart] Creating pid file: /home/zach/.ipython/profile_default/pid/ipcluster.pid
2021-04-23 10:06:33.636 [IPClusterStart] Starting Controller with LocalControllerLauncher
2021-04-23 10:06:34.638 [IPClusterStart] Starting 8 Engines with LocalEngineSetLauncher
2021-04-23 10:07:05.411 [IPClusterStart] Engines appear to have started successfully
2021-04-23 10:07:08.690 [IPClusterStart] ERROR | IPython cluster: stopping
2021-04-23 10:07:08.690 [IPClusterStart] Stopping Engines...
2021-04-23 10:07:11.694 [IPClusterStart] Removing pid file: /home/zach/.ipython/profile_default/pid/ipcluster.pid

This is on both my local and remove Ubuntu machines. Here is some version info:

local machine
ipython version 7.22.0
Python 3.8.5
ipyparallel 6.3.0
ipykernel 5.5.3

remote machine
Python 3.6.9
ipython 7.16.1
ipyparallel 6.3.0
ipkernel 5.4.2

Things I have tried:
copying directory
restarting
upgrading everything
deleting ipython pid and engines.json files
ls -al to find files in the problem directory that might cause an issue.
deleting __pycache__

It was working well before today. Last tried several days ago, when it was working. Unfortunately the directory that is not working is the one I always use.