Can't activate some clients

[lcp 0]

I recently upgraded from eset 5 to 6.5 and I am having trouble activating all my clients.  Most of they will activate, but I currently have 48 computers that will not activate through the ERA activation task.  I am able to contact these machines, I can even send commands to them (reboot, policy change), but the activation comes back as failed for them.  The rest of my machines are working fine.  Any ideas?

 

The machines range in vender and OS.  from windows 7 to windows 10.  I have HP, Dell, and lenovo machines.  The ones that activate and the ones that don't activate are found in all the range.  I can't seem to find a common issue that all the ones that will not activate share.

Edited June 29, 2017 by lcp

[MartinK 378]

Have you tried to activate failing client manually, i.e. from EES/EAV interface? Even in case of failure, more detailed error message may be provided -> can be used to search for error code in ESET KB2434. Most common cause of this issue is either missing internet connectivity to ESET servers (broken HTTP proxy configuration) and problems with TLS connection (is there any proxy/firewall with enabled TLS introspection?).

[lcp 0]

I tried to activate on the client and recieved the ACT .21 error.