SIMM Agent reload command fails

Hi

I have a problem with ssim agent connecting and getting its config from the SSIM server.

It bootstraps with no problem, I can ping both directions by name and by ip, to and from the siim server and agent.

but when i run option 3 reload agent configuration it returns with

Agent command cannot be executed
Read timed out.

the agent and collector is unknown in the visualiszer table veiw.

I have two machines at the end of the VPN that this connects over one works fine the other fails I have tried all sorts of things but getting nowhere.

any suggestions greatly appreciated