Sorry to hear you are having trouble.
I have separated home and office devices via different subnets.
That is why it is not working.
I have configured port forwarding from primary PC IP to secondary laptop IP to allow incoming traffic from WAN port to reach secondary laptop IP.
The best you may be able to hope for in resolving this is to ensure that the MP ports are also mapped:
Rule Name Port/.exe
Multiplicity Service 30564
Multiplicity Clipboard 30565
Multiplicity Application (clipboard) Multipl2.EXE
Multiplicity Audio Service 30567
Multiplicity Remote Screen Service 30569 (For Multiplicity 3 only)
Multiplicity Application (Remote screen control
MPRDP64.EXE (For Multiplicity 3 only)
And that you are using the IP and not the hostname, ie:
I cannot guarantee it will work, however.
Stardock Support Manager