On client machines, csampmux starts automatically when the first AutoSys client utility command is issued.
This can sometimes be an issue if the user lacks sufficient permissions.
Product: Workload Automation AE
The recommendation is to start csampmux before any user tries to issue AutoSys commands.
On UNIX/LINUX you could add the startup for csampmux in the WA AGENT startup script (waae-agent-WA_AGENT).
This way if the agent is set to start at boot time it would start csampmux as well.
If the agent is not configured to start at boot time you can create your own startup script in the boot area of your system to start csampmux as root.
On Windows there is "CA connection broker" service that can be set to start automatically.