too many authentication failures with ssh

The reason for the error "too many authentication failures" was the presence of too many ssh keys in my .ssh directory and the solution was to add the option IdentitiesOnly like

ssh -o "IdentitiesOnly=true" -i key.pem user@server.tld

or for password-based login, can also use

ssh -o PreferredAuthentications=password -o PubkeyAuthentication=no user@server.tld