You can use the following commands to verify that a license server is up and running, and to determine how many licenses it has in total, and how many are in use. In each option, replace adsk_server.lic with the actual license file name.
lmutil lmstat -a -c adsk_server.lic
/usr/local/flexnetserver/lmutil lmstat -a -c /var/flexlm/adsk_server.lic
/opt/flexnetserver/lmutil lmstat -a -c /var/flexlm/adsk_server.lic