Anti-malware engine offline issue may be observed in Deep Security Virtual Appliance (DSVA) deployment with Guest Introspection installed in NSX 6.4.1. You may find some EPSec-related errors such as below from ESXi.
read_key database operation failed for key xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx: No namespace found
Guest: vsep: AUDIT: VFileSocketMgrCloseSocket : Mux is disconnected
This issue in DSVA deployment may be caused by a known issue of NSX 6.4.1. For workaround and details, refer to this VMware article: Services and performance impact with Guest Introspection installed in NSX 6.4.1 (56734).