Nginx: [warn] could not build optimal server_names_hash

Last night when reload nginx I got this warning:

nginx: [warn] could not build optimal server_names_hash, you should increase either server_names_hash_max_size: 512 or server_names_hash_bucket_size: 64; ignoring server_names_hash_bucket_size

And it seems the new site created can’t be opened (the sad face with Don’t Panic notification page).
Maybe (I’m not sure) it was since updating bench to version 5.6.0.

What is it?
And what should I do?

Hi,

Have you tried bench setup nginx , or increasing the hash size as described here: https://stackoverflow.com/questions/13895933/nginx-emerg-could-not-build-the-server-names-hash-you-should-increase-server

Yes, I had done both before posting this.
Turn out I entry it wrong.
After your reply I got curious and try again.
It is a success with server_names_hash_bucket_size 128;
Thanks.

I guess (not sure how to confirm this) after adding the line, the bench setup nginx stop updating config list (not adding newsite, not removing dropped site, etc)
Can anyone help how to confirm the problem and resolve it?

Thank you