PuTTY Fatal Error: expected key exchange group packet from server

I had this same issue and to fix it i change the key exchange algorithm.

In putty settings under connection->ssh->kex I moved Diffie-Hellman group 14 to the top of the list and Diffie-Helman group exchange to the bottom. this solved the issue.

You can enable logging of sshd which can give you more details about the error.

To enable logging, edit etc/ssh/sshd_configfile and add the following line:

LogLevel DEBUG2

Reload sshd config:

systemctl reload sshd

Debug message will be logged to the file /var/log/secure

tail -f /var/log/secure

yes, it worked.

Root cause: Windows system was running on old version Putty using 1024 key. RHEL need new version ssh client because in RHEL 7 key is 2048.

Below option worked for me as well. Thanks a lot

In putty settings under connection->ssh->kex I moved Diffie-Hellman group 14 to the top of the list and Diffie-Helman group exchange to the bottom. this solved the issue.

Below option worked for me as well. Thanks a ton

In putty settings under connection->ssh->kex I moved Diffie-Hellman group 14 to the top of the list and Diffie-Helman group exchange to the bottom. this solved the issue.

Regards,

the setting doesn't save where open is not there after you move the Diffie-Hellman group 14 to the top.

i am getting the same problem while doing PSCP  from windows to centos 7.6 does anyone know how to solve the issue ? 

I am using below command.

pscp -i  keyfile sourcefile  user@1.2.3.4:/home/user