Hello,
I have forwarded your problem/question to Stardock Support Team for their assistance. Please keep an eye on this thread for any updates. We appreciate your feedback and patience.

Basj,
Stardock Community Assistant

Hi hishamzr,

Thanks for posting.  There are some things you'll want to make sure are setup correctly:

1. First, make sure you have the latest version of Multiplicity 4 on both Primary and Secondary computers. 

This can be checked by going to the following file path: 

C:\Program Files (x86)\Stardock\Multiplicity

Then right click MulticityConfig.exe and select Properties, then find the "File version" under the Details tab:

If the file version is not the same on both computers, you can retrieve the latest version to download and install it on each from this link:

https://www.stardock.com/support/product-key-retrieval

2. Once you're sure you have matching versions of Multiplicity 4 on each computer, then ensure the Encryption Key matches on all computers (see screenshot below).  

3. You'll also want to make sure the passcode on the Secondary is the same passcode used to add the computer as a KVM connection.

The Encryption Key and passcode can each be set from the Security tab on both Primary and Secondary:

Please let us know if these steps help to resolve the issue.

Best regards,

Adam McGuinness
Stardock Customer Support Specialist

I can understand the confusion but you seem to be thinking you need this set (and have set it)

With that set, you likely dont see that the KVM remote you are connecting to has a passcode prompting (what you would tell the Primary user to use to connect).

Uncheck that and it should be fine.

Sean Drohan
Stardock Product Lifecycle Manager

Do any of the computers have more than one network adapter or more than one up address per adapter?

If you run the purge on both PCs, install, and set up from scratch, does it work then

https://support.stardock.com/space/SHC/1347158073/Multiplicity+purging+and+re-installing

Sean Drohan
Stardock Product Lifecycle Manager