Imposibilidad de acceder via SSH desde otro Mac

En principio, siempre he podido acceder via ssh desde todos mis equipos locales, a el imac.

Desde el otro dia recibo un mensaje:

debug2: we sent a publickey packet, wait for reply
Authentication failed

Investigando, ya que tengo claro que la key es corecta revise el log de sshd en el iMac.

cat /var/log/system.log | grep sshd
May  1 16:34:06 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.08CBDEC5-F668-4AE2-B754-26C95478162B[3384]): Service exited with abnormal code: 255
May  1 16:35:05 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.D4422E1F-1A80-4FAE-8029-18B3BB68703C[3410]): Service exited with abnormal code: 255
May  1 16:36:55 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.0C386073-8128-401C-8F15-EF9C71A234A4[3476]): Service exited with abnormal code: 255
May  1 16:37:30 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.8A20EE1F-0895-4182-902F-0FCB9CCAA7A1[3484]): Service exited with abnormal code: 255
May  1 16:38:45 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.B4CA7459-68C5-4E6C-813E-EFAF8677CA8B[3538]): Service exited with abnormal code: 255
May  1 16:46:12 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.E3CBAF98-31B6-4CBA-8D90-06E642E2D743[3774]): Service exited with abnormal code: 255
May  1 16:46:46 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.968EB3D0-AAB1-46D1-B357-60D888AD7664[3820]): Service exited with abnormal code: 255
May  1 16:46:54 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.5CC5A2AD-0A53-4D58-92E8-5D3C5E624F0E[3823]): Service exited with abnormal code: 255
May  1 16:47:00 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.14BEF7AC-7F73-415F-8D20-C2ED5F7CCAE4[3826]): Service exited with abnormal code: 255
May  1 16:47:05 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.5339CF71-0619-47EB-B82C-26E92CB1A1F7[3829]): Service exited with abnormal code: 255
May  1 16:48:13 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.A0F2DFE5-75C4-4673-B6D0-24D69120CA45[3864]): Service exited with abnormal code: 255
May  1 16:48:29 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.0C3F527B-8278-4FC3-A9B9-98056B41B43C[3870]): Service exited with abnormal code: 255
May  1 16:52:30 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.0DF61FC6-4A93-48C6-BF5B-8407D1AB83C4[3944]): Service exited with abnormal code: 255
May  1 16:54:18 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.7A81F205-4D3F-472C-846F-F8EC77E8220E[3983]): Service exited with abnormal code: 255
May  1 16:58:03 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.B76F0DE2-A0A0-4258-A2B9-299B806E8D5F[4398]): Service exited with abnormal code: 255
May  1 16:59:08 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.BAF59C99-0A05-4675-BAA7-913442F881B2[4434]): Service exited with abnormal code: 255
May  1 17:11:23 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.B8885235-D0E5-4A5C-86CC-E5C608BDC3C3[4638]): Service exited with abnormal code: 255
May  1 18:30:24 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd.C023A7E3-2310-419E-90C5-0402ECEA6A9D[6503]): Service exited with abnormal code: 255

Asi que puse el tail y pare e inicie el servidor

sudo launchctl stop com.openssh.sshd
sudo launchctl start com.openssh.sshd

tail -f /var/log/system.log | grep sshd
May  1 21:06:03 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd[9957]): Service exited with abnormal code: 255

M 1 21:06:03 iMac-2 com.apple.xpc.launchd[1] (com.openssh.sshd[9957]): Service exited with abnormal code: 25

Que puede estar ocurriendo?