Notifications are not queued nor sent

First, sorry if this is a duplicate issue,
I found there are many related issues for this.
but I am not using OG or Mimemail, and I dont want to send mails for own posts.
Message Debug shows "No rows in queue".

After saving a new content there is no records in notifications/queue tables.

But with same settings and codebase it is working for another database. I am sure the settings are same.

Please let me know how to trace it?