SMS security code. Define site

Question

Burglary protection

The second day I receive SMS from some service with a security code. The problem is that I can not determine from which service it is.
phone: [phone]
message: "Your security code is 123456. Enjoy!"
I tried to call the number, the subscriber does not answer. Search by phone in Google did not give results, the text of SMS does not find either.

Answer 1

This is Dropbox.