Unable to negotiate with 10.10.140.50 port 22: no matching cipher found. Their offer: aes256-gcm,aes256-cbc

[jcb913]

Describe the problem
I can back up my data without any problems on approximately 350 devices. However, I can't do it on some cisco switch devices because the SSH connection cannot be established. I get this error Unable to negotiate with 10.10.140.50 port 22: no matching cipher found. Their offer: aes256-gcm,aes256-cbc

my oxidized ~/.config/oxidized/config configuration

vars:
  ssh_kex: "diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256"
  ssh_encryption: "aes256-gcm@openssh.com,aes256-gcm,aes256-cbc,aes128-cbc,3des-cbc"
  ssh_hmac: "hmac-sha2-256,hmac-sha1,hmac-md5"

Oxidized Logs

Unable to negotiate with 10.10.140.50 port 22: no matching cipher found. Their offer: aes256-gcm,aes256-cbc

W, [2026-04-06T14:36:26.364346 #3761002]  WARN -- : 10.10.140.11 raised Net::SSH::ConnectionTimeout (rescued RuntimeError) with msg "timeout during server version negotiating"
D, [2026-04-06T14:36:26.364679 #3761002] DEBUG -- : lib/oxidized/node.rb: Oxidized::SSH failed for 10.10.140.11
D, [2026-04-06T14:36:26.367092 #3761002] DEBUG -- : lib/oxidized/worker.rb: 1 jobs running in parallel
D, [2026-04-06T14:36:26.367217 #3761002] DEBUG -- : 10.10.140.11 raised Errno::ECONNREFUSED with msg "Connection refused - connect(2) for "10.10.140.11" port 23"
D, [2026-04-06T14:36:26.368335 #3761002] DEBUG -- : lib/oxidized/node.rb: Oxidized::Telnet failed for 10.10.140.11
D, [2026-04-06T14:36:26.368648 #3761002] DEBUG -- : lib/oxidized/job.rb: Config fetched for 10.10.140.11 at 2026-04-06 11:36:26 UTC
W, [2026-04-06T14:36:27.368334 #3761002]  WARN -- : ios/10.10.140.11 status no_connection, retries exhausted, giving up

Running environment :

• OS: [Ubuntu 22.04.5 LTS]
• oxidized version: [0.30.1]
• oxidized-web version: [0.13.1)]
• I'm having trouble with the device : Cisco C9200L-48P-4X,
• Devices ssh info:
  Connection Version Mode Encryption Hmac State Username
  0 2.0 IN aes256-cbc hmac-sha2-256 Session started
  0 2.0 OUT aes256-cbc hmac-sha2-256 Session started
• oxidized model name: ios

Additional context
I really need your help. Thank you so much in advance.