cant connect from VM1 to VM2 - ssh

Question

I have 2 virtual machines on my computer created with Vagrant.
on VM1 I create SSH key with ssh-keygen. Then copied id_rsa.pub into authorized_keys on VM2.
When I try to connect to VM2 using ssh 172.28.128.18, the connection is failed with following error
The authenticity of host '172.28.128.18 (172.28.128.18)' can't be established.
ECDSA key fingerprint is SHA256:YJ0CDFr9UcEBZkY1ajZRFg3Zx9uksZcv/i3fpC8gqdY.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '172.28.128.18' (ECDSA) to the list of known hosts.
vagrant#172.28.128.18: Permission denied (publickey).
With ssh -v vagrant#172.28.128.18 I have an other error:
OpenSSH_8.2p1 Ubuntu-4ubuntu0.3, OpenSSL 1.1.1f 31 Mar 2020
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug1: Connecting to 172.28.128.18 [172.28.128.18] port 22.
debug1: Connection established.
debug1: identity file /home/vagrant/.ssh/id_rsa type 0
debug1: identity file /home/vagrant/.ssh/id_rsa-cert type -1
debug1: identity file /home/vagrant/.ssh/id_dsa type -1
debug1: identity file /home/vagrant/.ssh/id_dsa-cert type -1
debug1: identity file /home/vagrant/.ssh/id_ecdsa type -1
debug1: identity file /home/vagrant/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/vagrant/.ssh/id_ecdsa_sk type -1
debug1: identity file /home/vagrant/.ssh/id_ecdsa_sk-cert type -1
debug1: identity file /home/vagrant/.ssh/id_ed25519 type -1
debug1: identity file /home/vagrant/.ssh/id_ed25519-cert type -1
debug1: identity file /home/vagrant/.ssh/id_ed25519_sk type -1
debug1: identity file /home/vagrant/.ssh/id_ed25519_sk-cert type -1
debug1: identity file /home/vagrant/.ssh/id_xmss type -1
debug1: identity file /home/vagrant/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.3
debug1: Remote protocol version 2.0, remote software version OpenSSH_8.2p1 Ubuntu-4ubuntu0.3
debug1: match: OpenSSH_8.2p1 Ubuntu-4ubuntu0.3 pat OpenSSH* compat 0x04000000
debug1: Authenticating to 172.28.128.18:22 as 'vagrant'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: chacha20-poly1305#openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305#openssh.com MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:YJ0CDFr9UcEBZkY1ajZRFg3Zx9uksZcv/i3fpC8gqdY
debug1: Host '172.28.128.18' is known and matches the ECDSA host key.
debug1: Found key in /home/vagrant/.ssh/known_hosts:1
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey in after 134217728 blocks
debug1: Will attempt key: /home/vagrant/.ssh/id_rsa RSA SHA256:1cq8iCIBMZrwP6BVucSZx4Luk3LfTAf/XOfovgHiW/Y
debug1: Will attempt key: /home/vagrant/.ssh/id_dsa
debug1: Will attempt key: /home/vagrant/.ssh/id_ecdsa
debug1: Will attempt key: /home/vagrant/.ssh/id_ecdsa_sk
debug1: Will attempt key: /home/vagrant/.ssh/id_ed25519
debug1: Will attempt key: /home/vagrant/.ssh/id_ed25519_sk
debug1: Will attempt key: /home/vagrant/.ssh/id_xmss
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,sk-ssh-ed25519#openssh.com,ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ecdsa-sha2-nistp256
#openssh.com>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /home/vagrant/.ssh/id_rsa RSA SHA256:1cq8iCIBMZrwP6BVucSZx4Luk3LfTAf/XOfovgHiW/Y
debug1: Authentications that can continue: publickey
debug1: Trying private key: /home/vagrant/.ssh/id_dsa
debug1: Trying private key: /home/vagrant/.ssh/id_ecdsa
debug1: Trying private key: /home/vagrant/.ssh/id_ecdsa_sk
debug1: Trying private key: /home/vagrant/.ssh/id_ed25519
debug1: Trying private key: /home/vagrant/.ssh/id_ed25519_sk
debug1: Trying private key: /home/vagrant/.ssh/id_xmss
debug1: No more authentication methods to try.
vagrant#172.28.128.18: Permission denied (publickey).
What is the reason of failing connecting to VM2?
on VM2
sudo tail -f /var/log/auth.log
server sshd[2509]: Connection closed by authenticating user vagrant 172.28.128.12 port 56446 [preauth]
Same problem is, when I try to connect from VM2 to VM1.