Re: unsupported dictionary type

Please append this line to /etc/postfix/main.cf, then restart Postfix service:

postscreen_cache_map = lmdb:$data_directory/postscreen_cache

Notes:

- iRedMail-1.7.4 doesn't set this postscreen_cache_map parameter in main.cf, but Postfix has default value "btree:$data_directory/postscreen_cache", this is why it uses btree.

- Postfix will generate file postscreen_cache.db automatically.

Please report whether it works for you or not.