vsphere_client_virgo.log show similar info:
[INFO ] health-status-85 c.v.v.v.cm.HealthStatusRequestHandler$HealthStatusCollectorTask Determined health status 'YELLOW: [(vmodl.LocalizableMessage) { dynamicType = null, dynamicProperty = null, key = webclient.memory.lowheap, arg = null, message = The server is running low on heap memory (>90% utilized.)}]' in 0 ms
7.x, 8.x, 8.0U3
The server is running low on heap memory
Increase heap memory via KB Manually increasing the heap memory of components in vCenter Server 7.x and 8.x