Thank you for your message.
Could you please let us know what version of Remote Utilities do you use? Please make sure that you update Viewer and Host to the most recent version - as of this writing, it's 184.108.40.206
or 6.12 Beta 1
In addition, before we proceed to further troubleshooting, please try referring to this KB troubleshooting guide
and see if any of the solutions listed there help to resolve the issue.
Namely, we recommend that you check if the required outbound ports are opened and not blocked by your firewall/not used by another software. For more information on the required ports please refer to this Documentation page
Please let us know if the issue persists.