[Michelle Hexnode 17 July 2018 Michelle Moderator]

Hey Felicia! This usually occurs when a user tries to enroll devices more than the number of licenses purchased.

You would not be able to enroll devices when the device limit is reached, but to solve this you can disenroll a device which is not in use from the device list and mark as disenrolled.

Once this is done, you would have the license required to enroll the device. You can also include additional licenses if needed from Admin > License.

Cheers!
Michelle Hendricks
Hexnode MDM.