Couldnt get SSH access to many IPs, these IP was accessable before update

[mymhich]

To Reproduce
Steps to reproduce the behavior:

1. Go to New Connection
2. in the Connect Manager I set the Host: 192.168.20.151
3. also I set the user name and password
4. See error "Session not connected"

5. the logs in my system as follow: 2025-10-07T15:23:07.646707+03:00 user-Vostro-15-3510 systemd[5307]: Started snap.muon-ssh.muon-ssh-9e787072-31e2-42f0-938e-ca5aa7259bf7.scope. 2025-10-07T15:23:08.121639+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:08 INFO [main] muon.app.App - 17.0.16 2025-10-07T15:23:08.173423+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:08 INFO [main] muon.app.App - Searching for known editors... 2025-10-07T15:23:08.196698+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:08 INFO [main] muon.app.App - Searching for known editors...done 2025-10-07T15:23:08.559310+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:08 INFO [main] muon.app.util.ScalingUtil - Graphics transform scale: 1.0 2025-10-07T15:23:08.559516+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:08 INFO [main] muon.app.util.ScalingUtil - DPI-based scale: 1.0104166 2025-10-07T15:23:08.559578+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:08 INFO [main] muon.app.util.ScalingUtil - Final detected scale factor: 1.0 2025-10-07T15:23:08.576371+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:08 INFO [main] muon.app.App - maxKeySize: 2147483647 2025-10-07T15:23:08.644806+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:08 ERROR [main] m.a.u.c.s.f.s.KubeContextSelectorPanel - Non-zero exit code 127 for command. 2025-10-07T15:23:08.644899+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:08 ERROR [main] m.a.u.c.s.f.s.KubeContextSelectorPanel - Error uploading K8s context pluging 2025-10-07T15:23:08.707729+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:08 INFO [Thread-0] muon.app.updater.UpdateChecker - Checking for url 2025-10-07T15:23:10.055290+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:10 INFO [Thread-0] muon.app.updater.UpdateChecker - Latest release: VersionEntry [tag_name=v3.0.0 value=300] 2025-10-07T15:23:11.410586+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:11 INFO [AWT-EventQueue-0] muon.app.common.PasswordStore - Password protection: PBEWithHmacSHA256AndAES_256 2025-10-07T15:23:11.574728+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:11 INFO [JediTerm-0] n.s.sshj.transport.random.JCERandom - Creating new SecureRandom. 2025-10-07T15:23:11.622187+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:11 INFO [JediTerm-0] muon.app.ssh.SSHHandler - enabled KeepAliveProvider 2025-10-07T15:23:11.809879+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:11 INFO [JediTerm-0] n.s.sshj.transport.TransportImpl - Client identity string: SSH-2.0-SSHJ_0.39.0 2025-10-07T15:23:11.957118+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:11 INFO [JediTerm-0] n.s.sshj.transport.TransportImpl - Server identity string: SSH-2.0-OpenSSH_7.4 2025-10-07T15:23:12.312757+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:12 INFO [JediTerm-0] muon.app.ssh.SSHHandler - Trying to get allowed authentication methods... 2025-10-07T15:23:12.895547+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:12 INFO [JediTerm-0] muon.app.ssh.SSHHandler - List of allowed authentications: [publickey, gssapi-keyex, gssapi-with-mic, password] 2025-10-07T15:23:12.895697+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:12 INFO [JediTerm-0] muon.app.ssh.SSHHandler - Trying auth method: publickey 2025-10-07T15:23:12.897287+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:12 ERROR [JediTerm-0] muon.app.ssh.SSHHandler - No suitable key providers 2025-10-07T15:23:12.897396+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: java.lang.IllegalStateException: No suitable key providers 2025-10-07T15:23:12.897461+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at muon.app.ssh.SSHHandler.authPublicKey(SSHHandler.java:126) 2025-10-07T15:23:12.897511+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at muon.app.ssh.SSHHandler.publicKeyAuth(SSHHandler.java:280) 2025-10-07T15:23:12.897580+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at muon.app.ssh.SSHHandler.connect(SSHHandler.java:226) 2025-10-07T15:23:12.897625+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at muon.app.ssh.SSHHandler.connect(SSHHandler.java:171) 2025-10-07T15:23:12.897684+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at muon.app.ui.components.session.terminal.ssh.SshTtyConnector.init(SshTtyConnector.java:52) 2025-10-07T15:23:12.897733+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at com.jediterm.terminal.ui.JediTermWidget$EmulatorTask.run(JediTermWidget.java:394) 2025-10-07T15:23:12.897771+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539) 2025-10-07T15:23:12.897813+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) 2025-10-07T15:23:12.897860+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) 2025-10-07T15:23:12.897940+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) 2025-10-07T15:23:12.898032+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at java.base/java.lang.Thread.run(Thread.java:840) 2025-10-07T15:23:12.898179+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:12 INFO [JediTerm-0] muon.app.ssh.SSHHandler - Trying auth method: gssapi-keyex 2025-10-07T15:23:12.898250+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:12 INFO [JediTerm-0] n.s.sshj.transport.TransportImpl - Disconnected - BY_APPLICATION 2025-10-07T15:23:12.900237+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:12 ERROR [JediTerm-0] m.a.u.c.s.t.ssh.SshTtyConnector - Unexpected value: gssapi-keyex 2025-10-07T15:23:12.900359+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: java.lang.IllegalStateException: Unexpected value: gssapi-keyex 2025-10-07T15:23:12.900430+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at muon.app.ssh.SSHHandler.connect(SSHHandler.java:237) 2025-10-07T15:23:12.900487+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at muon.app.ssh.SSHHandler.connect(SSHHandler.java:171) 2025-10-07T15:23:12.900537+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at muon.app.ui.components.session.terminal.ssh.SshTtyConnector.init(SshTtyConnector.java:52) 2025-10-07T15:23:12.900586+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at com.jediterm.terminal.ui.JediTermWidget$EmulatorTask.run(JediTermWidget.java:394) 2025-10-07T15:23:12.900771+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539) 2025-10-07T15:23:12.900831+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) 2025-10-07T15:23:12.900888+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) 2025-10-07T15:23:12.900947+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) 2025-10-07T15:23:12.901003+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: #011at java.base/java.lang.Thread.run(Thread.java:840) 2025-10-07T15:23:12.901090+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:12 INFO [JediTerm-0] m.a.u.c.s.t.ssh.SshTtyConnector - Terminal wrapper disconnecting 2025-10-07T15:23:12.901173+03:00 user-Vostro-15-3510 muon-ssh_muonssh.desktop[1369776]: 2025-10-07 15:23:12 INFO [JediTerm-0] m.a.u.c.s.terminal.TerminalComponent - Disconnected

Expected behavior
This IP was accessable before update the Muon SSH Client, and I can open SSH session from other application like Remmina

Desktop (please complete the following information):

• OS: Ubuntu 24.04.3 LTS
• Browser chrome,

please advice

[bobonov]

I had a similar issue and had to switch to another client.
The problem seems to be that the server is running an old SSH version that doesn’t support modern, more secure encryption algorithms.
As a result, the client and server can’t agree on a common cipher, and no encrypted channel can be established.

Updating the server’s SSH implementation, or enabling legacy ciphers on the client (if the Java SSH library allows it), should resolve the problem.