Kraken2 Databse for 16s full length metagenomics

Hi! I have 16s full length metagenome sequences. I would do taxonomic classification using Kraken2. I want to calssify my sequences to species level. But, when I use all database in Kraken2, I only get few species. Do you have solution for my problem and what databse should I use to get species level using 16s full length metagenome?
Thankyou