To restore automatic enrollment:

Log in to the sensor CLI.
Enable the CLI configuration mode:
appl-hostname > enable
appl-hostname # configure terminal
Restore automatic enrollment:
appl-hostname (config) # mvx cluster enrollment-service client enable
Verify your change:
appl-hostname (config) # show mvx cluster enrollment status
Save your change:
appl-hostname (config) # write memory

Example

The following example restores automatic enrollment on the nx-1 sensor.

nx-1 (config) # mvx cluster enrollment-service client enable 
nx-1 (config) # show mvx cluster enrollment status

MVX Cluster Enrollment Status
 
Enrollment Client:
    Status ok:                yes
    Status description:       enrolled
    Last checked at:          2019/07/11 22:51:01

Enrollment Service:
    Auto enabled:             yes
    Service address:          DTI (DTIUser@cloud.fireeye.com) 
    Preferred cluster:        any (less loaded)
    Cloud enabled:            yes 
    Cloud License enabled:    yes 
    Connect on demand:        yes

Broker Info:
    Cluster Name:             Cloud-MVX
    Broker Name:              Cloud-MVX-Broker
    Broker ID:                N/A
    Broker Address:           mvx.fireeyecloud.com
    Broker State:             Connected
    Failure Reason:           None
    Last Connection Attempt:  2019/07/07 22:13:58 
    Connection Last Formed:   2019/07/07 22:13:59 
    Connection Last Broken: