Perform the following in the Azure Console:

1. Go to Redis Caches.
2. For each Redis Cache:
3. Click on Advanced settings
4. Set the Allow access only via SSL to ‘Yes’
5. Select Save

Default Values:
By default, non-SSL access is disabled for new caches.

References:

1. https://docs.microsoft.com/en-us/azure/redis-cache/cache-configure#advanced-settings
2. https://docs.microsoft.com/en-us/azure/redis-cache/cache-faq#when-should-i-enable-the-non-ssl-port-for-connecting-to-redis