Cannot push to Heroku because key fingerprint

I had the same problem, I followed this post and others of the same kind without success :-((

Finally, I found the solution:I had to add my new rsa identity in my machine!

So, first of all I created a new rsa key:

ssh-keygen -t rsa -C "giordano.scalzo[at]gmail.com" -f  ~/.ssh/id_rsa_heroku

then added it to my machine

ssh-add ~/.ssh/id_rsa_heroku

and, finally, to Heroku

heroku keys:add ~/.ssh/id_rsa_heroku.pub

After that,

git push heroku master

worked like a charm!

Hope this helps.

I, too have multiple keys and multiple heroku accounts, so I come across this problem every few months. As mentioned Giordano Scalzo, Tom Carchrae, and user664833, the main problem is ssh-agent, which you control using the ssh-add command. The man page (man ssh-add) is actually pretty clear and concise, so check it out.

You can list all the keys that ssh-agent knows about with:

ssh-add -l

You can delete all the keys that ssh-agent knows about with:

ssh-add -D

Or delete a specific key with

ssh-add -d ~/.ssh/id_rsa_example_key_file_use_your_own

Don't worry! You aren't actually deleting the keys, only changing which ones ssh-agent automatically tries to use, for example, when you try to push to heroku. It's easy to add and delete keys as needed, so for me, when I get frustrated by this problem, the easiest way to fix it is to delete all the keys and add back in only the one I want to use at the moment.

ssh-add -Dssh-add ~/.ssh/id_rsa_example_use_this_one_i_mean_it

Your computer has an SSH key, but that SSH key is associated with another Heroku account.

If you need to use both accounts for different applications on the same computer you should make a new SSH key on your machine and upload it to Heroku:

$ ssh-keygen

Make sure to save it as '/Users/User/.ssh/new_id_rsa.pub' when the prompt asks you.

$ heroku keys:add /Users/User/.ssh/new_id_rsa.pub 

You then need to add an alternate host for heroku.com to your ~/.ssh/config:

Host heroku-altHostName heroku.comIdentityFile ~/.ssh/new_id_rsa

And then update the .git/config in your project to use the host alias:

[remote "heroku"]  url = git@heroku-alt:myapp.git  fetch = +refs/heads/*:refs/remotes/heroku/*

By choosing between heroku and heroku-alt in the remote of the .git/config files of specific projects you can manage which projects use which credentials.