heroku push error

$ git push heroku master

Counting objects: 392, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (383/383), done.
Writing objects: 100% (392/392), 1.40 MiB | 1999 KiB/s, done.
Total 392 (delta 22), reused 0 (delta 0)

-----> Heroku receiving push
-----> Launching........................................................... failed (Heroku error)
 !     Previous app version is still running, try pushing again shortly
 !     We've been notified, see http://support.heroku.com if the problem persists
 !     Heroku push rejected, testfire failed

error: hooks/pre-receive exited with error code 2
To [email protected]:xxxxxx.git
 ! [remote rejected] master -> master (pre-receive hook declined)