SDX has instance license (CNS_INST_CCS) checked from ADM. And SDX may report error "Appliance is running in grace. System will loose capacity after XYZ hours". 

Problem Cause

On ADM, more or more CNS_INST_CCS license(s) may expire. The following thing can be observed in ADM log: 

/var/log/license.log:
0:01:03 (CITRIX) EXPIRED: CNS_INST_CCS

Note: 
Networking issue between SDX and ADM may lead the issue too. If there is no expired license on ADM, please contact Citrix Support.