i tried from probe and it is ok.i can go from there no problem with this. i think this issue not becaouse of credentials. i have lots of servers like this and when i tried to discover again and again (6-7 times)with the just one ip, sometimes discover gives succes.But this is not all of them just someones.
i think in somewhere connection fail but i dont know where it is.
I have seen cases where WMI & NTCMD are not allowed on some servers and discovery only works if you use SSH.
Are they using a different SSH port apart from 22?
I will advise you validate with one or two servers that are failing by using putty for ssh (confirm the port configured on the remote server) and xcmd (ensure you have administrative permissions to view \\ServerName\ADMIN$) contents from your laptop.
If you are able to connect thats fine and if not, increase the timeout value for the discovery protocols and see what happens.