Unable to negotiate with [IP] port 22: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1

If you ever encounter this error, add the line

KexAlgorithms=+diffie-hellman-group1-sha1

at the end of your /etc/ssh/ssh_config file.

Bonus: One-Liner for the impatient

sudo echo „KexAlgorithms=+diffie-hellman-group1-sha1“ >> /etc/ssh/ssh_config