ESXi hosts always switch disconnecting and connected to vCenter, and ESXi always report flush firmware configuration

Hello,

I bought a new server HP DL380 Gen9, and installed ESXi5.5 U3 HPE.

Then I met a very strange matter.

I used vclient 5.5 U3 connect to ESXi host and found many tasks. These tasks will happen every minute.

I added this ESXi host in VCenter 6.5, then every some time(it looks like one minute), this host will disconnect from vcenter and display not responding about 2 seconds.

Whatever I change vcenter to 5.5 U3 or move this host into the same LAN with VCenter, this strange problem persists.

Could any one help me? Thanks.

Task Log in vclient:

Configure Storage I/O Control on datastore

Completed

vpxuser

2017/12/20 9:50:02

2017/12/20 9:50:02

2017/12/20 9:50:02

Update vSphere Distributed Switch list

Completed

vpxuser

2017/12/20 9:50:02

2017/12/20 9:50:02

2017/12/20 9:50:02

Select virtual NIC

135.251.69.111

Completed

vpxuser

2017/12/20 9:50:02

2017/12/20 9:50:02

2017/12/20 9:50:02

Flush firmware configuration

Completed

vpxuser

2017/12/20 9:50:01

2017/12/20 9:50:01

2017/12/20 9:50:02

Update management server IP

135.251.69.111

Completed

vpxuser

2017/12/20 9:50:01

2017/12/20 9:50:01

2017/12/20 9:50:01

Update global message

Completed

vpxuser

2017/12/20 9:50:01

2017/12/20 9:50:01

2017/12/20 9:50:01

Event Log  in vcenter:

Best Regards,

Xici