LHR NE40-8 router was monitored normally through DMS but suddenly the graphs were stuck and no data could be retrieved from the device. When double click on the router icon to launch Quidview, it is unable to connect to the specified IP.
After restart the router SNMP problem got solved and router got added into DMS successfully.
According to engineer:
Equipment cannot be monitored nor added through "add object" or "auto discovery" ever since a CE1 card encountered some problem. Their snmp configuration is correct and they can ping the device at 188.8.131.52.
But despite removing and adding the snmp configurations back, the device cannot be added nor monitored properly by the DMS and is still in blue color (in device navigator). Error message is displayed (as shown in attached screen capture) when user tries to add the device.
Both the equipment sysoid and device sysoid in DMS has been checked and found to be the same i.e.
Sysoid in DMS's TopoDB > tbl_DevType SQL table is "184.108.40.206.4.1.2011.2.31"
Sysoid found from equipment using MIB-browser is "enterprise.2011.2.31"