Editing the REDIS configuration is not a good solution, or not in my case. I use REDIS with another containers in the same host (GitLab and 2 more aplications) if REDIS is not exposed outside, is also secure without password.
It’s a BUG in version 20.0.1.1 of Nextcloud, you need to do something in Nextcloud to fix it.
In my case I deleted provisionally 3 lines, from 93 to 95 from lib/private/RedisFactory.php
