Nextcloud Server Error - Redis::pconnect(): Passing null to parameter #2 ($port) of type int is deprecated

Error message in Nextcloud logs:

Redis::pconnect(): Passing null to parameter #2 ($port) of type int is deprecated at /var/www/nextcloud/lib/private/RedisFactory.php#104

This error is caused by a missing port number in the Nextcloud redis configuration. To fix this error, specify the port number in the Nextcloud redis configuration (even if Redis is not setup on a TCP port):

Open Nextcloud configuration file config/config.php:

'redis' => [
    'host' => '/var/run/redis/redis.sock',
    'port' => 0,
    'timeout' => 1.5,
    ...
],