do you have VMAN Appliance or VIM in Orion?
If you have VMAN and it is really connection issue, we suggest to deploy Federated Collector on the site (where host is located), configure collector's connection with VMAN and let poll mentioned host via collector.
This will hopefully work + this should also save some network resources.
There is also KB article about this (especially second half of it):
Use federated collectors in Virtualization Manager
If this won't help, open case with support and we will try to find another solution.