Since you are entering through a portal, you belong to an organization. that authorizes licenses. Please contact you organization administrator to assign you to an add-0n Drone2Map license or a user type that includes Drone2Map.
As Jerry pointed out, the user must be assigned an add-on Drone2Map license or a user type that includes a Drone2Map license. In addition, Drone2Map will make a call to the license manager hosting a Drone2Map license. The communication between the two system used TCP/IP protocal through two specific ports, 27000 and another open port. If there is a firewall between the system, you must open these ports through the firewall. Below is a doc on how to configure the license manager through a firewall. The same rule applies to Concurrent Use and Named User with ArcGIS Enterprise. The error you mentioned refers to a failed attempt to connect to the license manager hosting the Drone2Map Named User license.
