1.5 DR problem

I have a strange problem with one of my dr slaves:
when DR starts it says in V-RAY messages window:

‘scene transferred to slave1’
‘server 192.xx.. scene loaded;starting render’ …but than in a while it is 'warning:render host unknown [ ip… ] is not responding

it’s working OK with my other slaves

That particular slave probably crashes at some point. Is there anything about it that is different from the others?

Best regards,
Vlado

no, exept that i first installed the dongle on it, then had to move it to another machine

Ok then, did you update the render slave to look for the license server on the new machine where you moved the dongle?

Best regards,
Vlado

yes, actually it did work properly for a while at some point, but than…
v-ray reinstall on the machine doesnt help