It is an authentication error. Here is the final part of the output (I changed the production ip address here to 111.11.11.111):
debug1: Next authentication method: publickey
debug1: Trying private key: /Users/user1/Library/Group Containers/E78WKS7W4U.io.coressh.ssh/.ssh/privatekey/id_rsa
debug3: sign_and_send_pubkey: RSA SHA256:aZx9T7BRYqok735awNDBrZjpFG9qzSHyLcfIp+kag5g
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
user1@111.11.11.111: Permission denied (publickey).
debug3: send packet: type 1
debug1: channel 0: free: direct-tcpip: listening port 0 for 111.11.11.111 port 43556, connect from 127.0.0.1 port 54335 to UNKNOWN port 54336, nchannels 1
debug3: channel 0: status: The following connections are open:
#0 direct-tcpip: listening port 0 for 111.11.11.111 port 43556, connect from 127.0.0.1 port 54335 to UNKNOWN port 54336 (t4 r0 i0/0 o0/0 fd 6/7 cc -1)
debug1: fd 0 clearing O_NONBLOCK
debug1: fd 1 clearing O_NONBLOCK
Killed by signal 1.
It seems the the proxy server is not passing the key to the production server. What is strange is that this was working before.