In order to enable the , it's mandatory to manage the Conditional Rule Settings first.

1

Click on Conditional Rule Settings to configure the User that the application will use to avaluate the conditional rules.

Administration → Add-Ons → Herzum Approval→ Conditional Rule Administration Conditional Rule Settings 

It is strongly recommended to use a system user for this setting due to this account will be automatically granted of browse permission on all JIRA projects.

Notice that, on changing this configuration, by setting a different user, the older user will have browse permission automatically removed on all your projects as well.

Conditional Rule Settings screen

2Click on the user picker button to get the list of available users and select one.

Conditional Rule Settings screen

3Save conditional rule settings.

Conditional Rule Settings screen