Intermittently, Multiplicity cannot find any of my other PCS. I have had this issue on and off and the only thing that fixes this seems to be a fresh install. All of my 6 PCs are on private networks, all of my passwords match, I have rebooted all machines in various order, all of the IP addresses match, firewall is set to allow the program, and all pcs have the latest version of the software. I just had this working on all 6 yesterday and today, with no changes it cannot find any of them. Please help.
As you would suspect, troubleshooting network issues is extremely difficult and much of the heavy lifting (troubleshooting and fixing) is up to the end user. What we have to do is demonstrate that the product works under normal network conditions. As you have stated, it does but something - over time - changes. Since Multiplicity has clearly not changed, something on the network, or the network itself, has. Some common changes
- VPN connections created \ terminated
- Connection medium changes (wireless, ethernet, etc)
- Firewalls
To assist as best we can, we direct clients here:
https://support.stardock.com/space/SHC/1287946260/Multiplicity+Connection+issues+101
It's comprehensive but it should be clear from it where our support shoreline begins and ends. Something you might consider (and is one of the items outside the our support scope) is statically assigning your private IP addresses to your PCs and having MP connect to those instead of the host names.

Again, there are other items that could help and are detailed in the noted support document but that is one you can try as well.
Adam McGuinness
Stardock Customer Support Specialist