Cygwin: ssh and ssh-keygen do not react at all

Question

I've got a strange behaviour of ssh and ssh-keygen: they do not react at all. Cygwin is started with admin rights and works normally. The host 192.168.1.1 is up and I can remote desktop to it:

When I try:

$ ssh -vvv [email protected]
OpenSSH_8.3p1, OpenSSL 1.1.1f  31 Mar 2020

I get only one line but nothing else, even if I wait hours. I reinstalled cygwin, openssh, I deleted the .ssh folders, no success.

When I enter

ssh-keygen -b 4096

nothing happens at all. For me it seems that the user interaction does not work. Any ideas?

Thanks

Update: I tried:

1. reinstalling cygin for all users, one user, running the installation with admin rights, without. No success.
2. Started ssh and ssh-keygen with an absolute path to make sure that the windows openssh is not used
3. Checked the folder permissions on .ssh

Here is my strace: Pastebin

Update 2: I found the following: if I run ssh-keygen or ssh often enough (!) it will sometimes work! Now that's weird.

Answer 1

Philippe had the right idea. Basically the citrix workspace app is crashing ssh cygwin. When I uninstalled citrix everything worked fine!