Vagrant stuck connection timeout retrying (Server refused our key) - ssh

Question

My vagrant was working perfectly fine last night. I've just turned the PC on, hit vagrant up, and this is what I get:
vagrant up
Bringing machine 'machine1' up with 'virtualbox' provider...
==> machine1: Checking if box 'puphpet/ubuntu1404-x64' is up to date...
==> machine1: Clearing any previously set forwarded ports...
==> machine1: Clearing any previously set network interfaces...
==> machine1: Preparing network interfaces based on configuration...
machine1: Adapter 1: nat
machine1: Adapter 2: hostonly
==> machine1: Forwarding ports...
machine1: 22 (guest) => 9180 (host) (adapter 1)
machine1: 22 (guest) => 2222 (host) (adapter 1)
==> machine1: Running 'pre-boot' VM customizations...
==> machine1: Booting VM...
==> machine1: Waiting for machine to boot. This may take a few minutes...
machine1: SSH address: 127.0.0.1:2222
machine1: SSH username: vagrant
machine1: SSH auth method: private key
machine1: Warning: Remote connection disconnect. Retrying...
machine1: Warning: Remote connection disconnect. Retrying...
machine1: Warning: Authentication failure. Retrying...
machine1: Warning: Authentication failure. Retrying...
machine1: Warning: Authentication failure. Retrying...
machine1: Warning: Authentication failure. Retrying...
machine1: Warning: Authentication failure. Retrying...
machine1: Warning: Authentication failure. Retrying...
machine1: Warning: Authentication failure. Retrying...
machine1: Warning: Authentication failure. Retrying...
When I tried to connect I see this:
Using username "vagrant".
Server refused our key
vagrant#127.0.0.1's password:
But my key file didn't change. There is similar question Vagrant stuck connection timeout retrying but there is other reason and it not helped me.
There is ssh-config
> vagrant ssh-config
Host machine1
HostName 127.0.0.1
User vagrant
Port 2222
UserKnownHostsFile /dev/null
StrictHostKeyChecking no
PasswordAuthentication no
IdentityFile "C:/puphpet/puphpet/files/dot/ssh/id_rsa"
IdentityFile "C:/Users/alexk/.vagrant.d/insecure_private_key"
IdentitiesOnly yes
LogLevel FATAL

Answer 1

Add the following line of code to C:\HashiCorp\vagrant\embedded\gems\gems\vagrant-1.8.5\plugins\guests\linux\cap\public_key.rb:
chmod 0600 ~/.ssh/authorized_keys
Original block:
if test -f ~/.ssh/authorized_keys; then
grep -v -x -f '#{remote_path}' ~/.ssh/authorized_keys > ~/.ssh/authorized_keys.tmp
mv ~/.ssh/authorized_keys.tmp ~/.ssh/authorized_keys
fi
New block:
if test -f ~/.ssh/authorized_keys; then
grep -v -x -f '#{remote_path}' ~/.ssh/authorized_keys > ~/.ssh/authorized_keys.tmp
mv ~/.ssh/authorized_keys.tmp ~/.ssh/authorized_keys
chmod 0600 ~/.ssh/authorized_keys
fi
I had the same problem and found the above solution here.