Fix connection problems

Start with the terminal’s ⋯ › Connection log, which shows each step and the login methods tried.

“Host key changed for …”

The server presented a different key from the saved one. Someone may be intercepting the connection, or the server was reinstalled.

Caution

Check with the server’s administrator. Choose Replace key only if you know the key changed.

The login is refused

Check the user name and password or key in the host’s editor. An SSH agent with many keys can hit the server’s limit; give the host its own key (Use an SSH agent).

An unknown host key is refused without asking

Settings › Connections & SSH › Unknown host keys is Strict, or a team policy requires it. Add the key to Known hosts first, or switch to Ask.

It times out

The address or port may be wrong, or a firewall drops the connection. Settings › Connections & SSH › Show which hosts answer puts a dot beside each host whose SSH port answers. A host behind a jump host is reached only through it (Connect through jump hosts).

“mosh-client not found”

Install Mosh, or turn off Mosh-compatible session for the host (Use Mosh). Hosts with jump hosts or a proxy can’t use Mosh.

A team host stops at “Changed by … at …”

Another member changed how the host connects since your last connection. Read the old and new values, and choose Connect only if you expected the change.

A port forward shows “Waiting for approval”

It listens on an address other devices can reach, or comes from a vault others can change. Start it, read what it opens and approve it (Approve a port forward).

Security key errors

See Fix security key problems.