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SSH Too Many Authentication Failures — Connection Rejected After Key Attempts

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Overview

Fix SSH 'Too many authentication failures' error when the SSH client tries too many keys before finding the correct one, exceeding the server's MaxAuthTries limit.

Key Details

  • SSH clients try all loaded keys (from ssh-agent and config) before falling back to password
  • If you have 5+ SSH keys loaded, the client may exhaust MaxAuthTries (default 6) before trying the right key
  • Each key attempt counts as an authentication try even if the key is wrong
  • The server disconnects after MaxAuthTries is reached, showing 'Too many authentication failures'
  • This commonly affects developers with multiple GitHub, GitLab, and server SSH keys

Common Causes

  • Too many SSH keys loaded in ssh-agent (each is tried sequentially)
  • SSH config (~/.ssh/config) not specifying which key to use for each host
  • Server MaxAuthTries set too low for the number of keys the client offers
  • IdentitiesOnly not set, causing the client to try agent keys in addition to configured keys

Steps

  1. 1Specify the correct key per host in ~/.ssh/config: Host server.com > IdentityFile ~/.ssh/server_key
  2. 2Add 'IdentitiesOnly yes' to the host config to use only the specified key (not agent keys)
  3. 3List loaded agent keys: 'ssh-add -l' — remove unnecessary keys with 'ssh-add -d key_file'
  4. 4Force password auth for testing: 'ssh -o PreferredAuthentications=password user@host'
  5. 5If server admin: increase MaxAuthTries in /etc/ssh/sshd_config (default is 6)

Tags

sshauthenticationtoo-many-failuresssh-agentkeys

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Frequently Asked Questions

By default, SSH offers all keys from ssh-agent and default key paths (~/.ssh/id_rsa, id_ed25519, etc.) to the server. Without IdentitiesOnly and IdentityFile in your config, every key is tried for every host.