ISSUE - Cannot access the Device Enrollment Program. Please contact your organization's administrators. [ConfiguratorUtility.error - 0x7531 (30001)]

I trying to activate supervisioned mode at my school's iPads, and it isn't working.

I'm using Apple Configurator 2 on my MacBook Pro.

I have 70 iPads to manage from the various versions, among them iPad 1, iPad 2 4th Generation and iPad Air 2.

The process starts correctly, but at the end this error appears, stating that my account can not access:

"ipadsaoluis@colegiosmaristas.com.br" - Can not access the Device Enrollment Program. Please contact your organization's administrators. [ConfiguratorUtility.error - 0x7531 (30001)]

what am I doing wrong?