People may confuse activation codes certificates with license activation keys.

Customers sometimes are provided with activation codes certificates.

Activation codes are not the same as license activation key.

In fact activation codes are used to generate the licenses.

Reference

Activate Junos OS Licenses 

https://www.juniper.net/documentation/us/en/software/license/juniper-licensing-user-guide/topics/topic-map/activate-license.html#activate-junos-os-licenses

Customer can download activation keys from the Juniper Agile Licensing Portal

https://license.juniper.net/licensemanage/

JTAC cannot Download activation keys from the Juniper Agile Licensing Portal because JTAC do not have access to the Juniper Agile Licensing Portal.

If you are a partner or customer and need license activation assistance please contact Juniper Networks Customer Care at https://www.juniper.net/support/requesting-support.html.