OEM Agent Home Page Shows ” Communication between the Oracle Management Service to the Agent is unavailable. Any features or displayed information requiring this communication will be unavailable”

After OMS upgraded to 13.4, the agent home pages are showing the following error:

Communication between the Oracle Management Service to the Agent is unavailable. Any features or displayed information requiring this communication will be unavailable

WORKAROUND

This is known issue because of SSLCipherSuites compatibility issue between OMS and Agents after OMS upgrading.

Run the following commands on EM agent server to resolve this issue:

$ emctl status agent

$ emctl pingOMS

$ emctl getproperty agent -name SSLCipherSuites
Oracle Enterprise Manager Cloud Control 13c Release 2
Copyright (c) 1996, 2016 Oracle Corporation.  All rights reserved.
SSLCipherSuites is unset; default value is SSL_RSA_WITH_RC4_128_MD5:SSL_RSA_WITH_RC4_128_SHA:SSL_RSA_WITH_3DES_EDE_CBC_SHA

$ emctl setproperty agent -name SSLCipherSuites -value TLS_RSA_WITH_AES_128_CBC_SHA:TLS_RSA_WITH_AES_256_CBC_SHA:RSA_WITH_AES_256_CBC_SHA256
Oracle Enterprise Manager Cloud Control 13c Release 2
Copyright (c) 1996, 2016 Oracle Corporation.  All rights reserved.
EMD setproperty succeeded

$ emctl getproperty agent -name SSLCipherSuites
Oracle Enterprise Manager Cloud Control 13c Release 2
Copyright (c) 1996, 2016 Oracle Corporation.  All rights reserved.
SSLCipherSuites=TLS_RSA_WITH_AES_128_CBC_SHA:TLS_RSA_WITH_AES_256_CBC_SHA:RSA_WITH_AES_256_CBC_SHA256

$ emctl stop agent

$ emctl start agent