Horizon fails when changing host IP

[George Rubin]

Horizon fails after login screen for creating a new session key.
Only after changing the following file with the new IP it works:
sed -i "s:10.20.20.1:<MY NEW IP>:g" /var/snap/microstack/common/etc/horizon/local_settings.d/_05_snap_tweaks.py

RuntimeError at /auth/login/
Unable to create a new session key. It is likely that the cache is unavailable.
Request Method: POST
Request URL: http://172.28.22.201/auth/login/
Django Version: 2.2.12
Exception Type: RuntimeError
Exception Value:
Unable to create a new session key. It is likely that the cache is unavailable.
Exception Location: /snap/microstack/233/lib/python3.8/site-packages/django/contrib/sessions/backends/cache.py in create, line 50
Python Executable: /snap/microstack/233/bin/uwsgi
Python Version: 3.8.5
Python Path:
['.',
 '',
 '/var/snap/microstack/common/etc/horizon/uwsgi/snap',
 '/usr/lib/python3.8',
 '/usr/lib/python3/dist-packages',
 '/snap/microstack/233/usr/lib/python3.8',
 '/snap/microstack/233/lib/python3.8/site-packages',
 '/snap/microstack/233/usr/lib/python3/dist-packages',
 '/usr/lib/python38.zip',
 '/usr/lib/python3.8/lib-dynload',
 '/snap/microstack/233/lib/python3.8/site-packages/openstack_dashboard']
Server time: Tue, 9 Nov 2021 12:14:27 +0000