Trial FortiToken Mobile cannot be used in HA load-balancing mode

Hello...

I am new to FortiAuthenticator and have inherited a couple of devices with a failed HA config.  In troubleshooting I have removed the nonoperational slave and am trying to re-add it.  When re-adding the slave device I get the error message "Trial FortiToken Mobile cannot be used in HA load-balancing mode. Please disassociate them from any user."  How do I identify which account is using the trial licenses?  Is it possible to remove the trial license all together so they don't accidentally get used again?

Thank you