The agent icon does not show for multiple users when logged into a windows server ( including Terminal servers )
Previous attempts to resolve
In an attempt to resolve this you have tried to add the "-remote" option to registry as per this KB or the KCA course instructions.
The 6.3 "Kaseya Certified Administrator" course states the following.
The Registry change
Prior to the registry change if you remoted to a server you may not see the agent icon in the system tray. Post the change if you Log off and back in you will see the Agent icon. This still works as described in the current and previous versions of Kaseya at the time of writing.
The last line of the documentation (Log off and log back in, You will see the icon) assumes that there are no other users logged on at the time.
Making this registry change will not enable the agent icon to be displayed in every session when multiple users connect to the server (like a terminal server). The Agent icon can only be shown once per server. The first user that logs into the server will be the only one able to see the icon.
There is no known resolution or workaround at this time.