I get the error of " Cannot read/write '/var/lib/salt/.ssh/known_hosts" when i try to add (bootstrap) a machine.

Hi,
I have installed a trial version of suse manager 4.0 with the intent to purchase.
I have installed it from scratch from DVD. I have a subscription for sles 15 and got the 60 day trial.
I have updated sles 15 to 15 sp1 and installed all the latest updates for it.
when I login to suse manager web UI and go to the boot stap page to start to add machines, I end up with the error of "Cannot read/write '/var/lib/salt/.ssh/known_hosts"

I have checked the permissions on the server and they are salt:salt.
I have given full rights to all to see if that's an issue, and the web UI still throws up the error.

I did log a support call about this and got closed as they don't support the trial version of it.

I have done a search of the error and found this
https://www.suse.com/support/kb/doc/?id=7023506
but it's to do with 3.1 and 3.2.

I'm now stuck on what to do, and with the 60 day timer continuing to count down.

Cheers for the help

Tim Paice
Systems engineer.