Set OEM page to NOT Timeout

OEM page login session expires to the time what ever you have set in OEM properties and if we want to change to the time depending on your Organization policies then please follow below step

Here i'm trying to set it to NOT expire / Unlimited to do so 

Check the current value from OMS server 

[oracle@OMSHOSTSRVR bin]$ ./emctl get property -name oracle.sysman.eml.maxInactiveTime
Oracle Enterprise Manager Cloud Control 13c Release 2
Copyright (c) 1996, 2016 Oracle Corporation.  All rights reserved.
SYSMAN password:
Value for property oracle.sysman.eml.maxInactiveTime for oms All Management Servers is null

Set the property value with "-1" which is unlimited

[oracle@OMSHOSTSRVR bin]$ ./emctl set property -name oracle.sysman.eml.maxInactiveTime -value -1
Oracle Enterprise Manager Cloud Control 13c Release 2
Copyright (c) 1996, 2016 Oracle Corporation.  All rights reserved.
SYSMAN password:
Property oracle.sysman.eml.maxInactiveTime has been set to value -1 for all Management Servers
OMS restart is not required to reflect the new property value

[oracle@OMSHOSTSRVR bin]$ ./emctl get property -name oracle.sysman.eml.maxInactiveTime
Oracle Enterprise Manager Cloud Control 13c Release 2
Copyright (c) 1996, 2016 Oracle Corporation.  All rights reserved.
SYSMAN password:
Value for property oracle.sysman.eml.maxInactiveTime at Global level is -1

BOUNCE the OMS to take affect the changes made

$ emctl stop oms -all
$ emctl start oms 

Referrence:
EM 12c : How to Change the Timeout Window of an emcli Session (Doc ID 1589497.1)
How to Change the Default Login (Idle) Timeout Value for the Enterprise Manager Cloud Console Connections? (Doc ID 1385996.1)