Open Mouse Without Borders on both computers
Click Advanced
Uncheck Require security key for pairing
Uncheck Require password for connection if available
Recreate the connection using the new pairing code
Make sure both PCs are on the same trusted network
If prompted by Windows, allow Mouse Without Borders through the firewall
If the option is unavailable, update Mouse Without Borders to the latest version
If it still requires a password, reset the connection and pair again with the new settings