Flask app no longer working from cygwin when set to developer mode

This problem occurred immediately after attempting to run my python flask app in the background using:

$python app.py &

This immediately failed. Afterwards, any future attempts to run the app, which I have done before with no problem, ending up providing this error:

 $ python app.py
Running on http://127.0.0.1:8050/
Debugger PIN: 962-843-370
 * Serving Flask app "app" (lazy loading)
 * Environment: development
 * Debug mode: on
      2 [main] python3.6m 37104 child_info_fork::abort: unable to remap _lbfgsb.cpython-36m-x86_64-cygwin.dll to same address as parent (0x48E0000) - try running rebaseall
Traceback (most recent call last):
  File "app.py", line 644, in <module>
    app.run_server(debug=util.DEBUG)
  File "/cygdrive/c/Users/mkupfer/Desktop/my_documents/01_Visualizations/eurostat/venv/lib/python3.6/site-packages/dash/dash.py", line 1293, in run_server
    **flask_run_options)
  File "/cygdrive/c/Users/mkupfer/Desktop/my_documents/01_Visualizations/eurostat/venv/lib/python3.6/site-packages/flask/app.py", line 943, in run
    run_simple(host, port, self, **options)
  File "/cygdrive/c/Users/mkupfer/Desktop/my_documents/01_Visualizations/eurostat/venv/lib/python3.6/site-packages/werkzeug/serving.py", line 812, in run_simple
    reloader_type)
  File "/cygdrive/c/Users/mkupfer/Desktop/my_documents/01_Visualizations/eurostat/venv/lib/python3.6/site-packages/werkzeug/_reloader.py", line 275, in run_with_reloader
    sys.exit(reloader.restart_with_reloader())
  File "/cygdrive/c/Users/mkupfer/Desktop/my_documents/01_Visualizations/eurostat/venv/lib/python3.6/site-packages/werkzeug/_reloader.py", line 132, in restart_with_reloader
    close_fds=False)
  File "/usr/lib/python3.6/subprocess.py", line 267, in call
    with Popen(*popenargs, **kwargs) as p:
  File "/usr/lib/python3.6/subprocess.py", line 709, in __init__
    restore_signals, start_new_session)
  File "/usr/lib/python3.6/subprocess.py", line 1275, in _execute_child
    restore_signals, start_new_session, preexec_fn)
BlockingIOError: [Errno 11] Resource temporarily unavailable

The error seems to stem from running in developer mode since when I run with app.run_server(debug=False) (btw, util.DEBUG is set to True in my local environment), the app works fine, but then I don’t get hot reloading which is important for me.

I’ve tried rebasing cygwin as per this post https://superuser.com/a/194537/276726, but this didn’t fix anything.

I've also tried creating a special rebase file following the steps in this post, but that didn't help either.

The app works in development mode from my windows command line, so that is my temporary fix for now, but I would love to get my Cygwin setup running properly again.

Thanks for the help!

from Flask app no longer working from cygwin when set to developer mode