This month, I have earned 16 points. Until yesterday, my reputation score was correct, but I just logged into my Stack Overflow account and now it is showing -1 reputation for this month.
Is this a bug? What might be the problem?
Likely someone removed "Accepted Answer" from one of your questions... – davidsleeps
Is it possible to know which answer is removed from "Accepted answer"... – Chandan Shetty SP
Yes, if you lost 15 points (why weren't those detailed numbers there in your original question?), then davidsleeps is exactly right about what happened. One of your previously accepted answers was unaccepted by the person who originally asked the question.
That is perfectly acceptable behavior, of course, but you don't (at least currently) get a notification when it happens. The only way to find out is to go through your answers (displayed in your profile) one-at-a-time and see which one used to be accepted but isn't anymore. It's a fairly tedious, painstaking process for minimal gain. The best option is really just to learn to live with a little bit of rep fluctuation.
And as otherwise suggested in the comments, in the future you can audit your own reputation using the spiffy graphical reputation history available in your user profile, and/or the text-based audit accessible at the
/reputation page: https://stackoverflow.com/reputation