W3TC option grayed out

Let me start by saying I’ve read all of the redis posts in this forum and have followed the instructions in the FAQ and yet the redis option is still grayed out.

(BTW, the FAQ shows two colons between the host and port, I expect it should only be one)

I’ve created an instance of Azure Redis which I’m attempting to use. I’ve enabled it to allow non-SSL connections on 6379.

The db-config.php file in the /wp-contnet/plugins/w3-total-cache.ini folder contains:

define( ‘W3TC_CONFIG_CACHE_ENGINE’, ‘redis’);
define( ‘W3TC_CONFIG_CACHE_REDIS_SERVERS’, ‘my-redist-host-fqdn:6379’ );
define( ‘W3TC_CONFIG_CACHE_REDIS_PERSISTENT’, true );
define( ‘W3TC_CONFIG_CACHE_REDIS_DBID’, 0 );
define( ‘W3TC_CONFIG_CACHE_REDIS_PASSWORD’, ‘my-actual-password’ );

From an SSH console I executed: curl -v telnet://my-redist-host-fqdn:6379 and the connection succeeded.

I tried deactivating/activating the plugin and even tried two colons between the host and port, and yet the redis option remains grayed out for both page cache and object cache.

What am I missing?