If you look at the interface, it shows as purple and shows snmp uknown, despite the device SNMP credentials being correct and verified.
This started happening around the same time OpManager started throwing an error in its stderr logs:
:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]: java.lang.NullPointerException|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at com.adventnet.netflow.api.handler.DeviceApiHandler.getTrafficData(DeviceApiHandler.java:284)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at java.lang.reflect.Method.invoke(Unknown Source)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at com.adventnet.netflow.api.handler.DefaultApiHandler.processRequest(DefaultApiHandler.java:81)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at com.adventnet.me.opmanager.server.api.OpManagerAPIServlet.processRequest(OpManagerAPIServlet.java:311)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at com.adventnet.me.opmanager.server.api.OpManagerAPIServlet.doGet(OpManagerAPIServlet.java:106)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at com.adventnet.nms.webclient.login.NTLMV2CredentialAssociationFilter.doFilter(NTLMV2CredentialAssociationFilter.java:37)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at com.adventnet.nms.webclient.login.NTLMV2Filter.doFilter(NTLMV2Filter.java:108)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at com.adventnet.nms.webclient.login.OPMSecurityFilter.doFilter(OPMSecurityFilter.java:102)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at com.adventnet.netflow.filters.NFACredentialFilter.doFilter(NFACredentialFilter.java:75)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at com.adventnet.filters.ParamFilter.doFilter(ParamFilter.java:30)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at com.adventnet.authentication.filter.AssociateCredential.doFilter(AssociateCredential.java:100)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at com.adventnet.nms.webclient.login.OpmSkipFilter.doFilter(OpmSkipFilter.java:100)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)|
[10:38:37:921]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.authenticator.SingleSignOn.invoke(SingleSignOn.java:291)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1086)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:659)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1558)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1515)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)|
[10:38:37:937]|[03-22-2017]|[SYSERR]|[INFO]|[399]:
at java.lang.Thread.run(Unknown Source)|
[10:39:31:218]|[03-22-2017]|[SYSERR]|[INFO]|[451]: Error in InterfaceStatus poll pdu There is no such variable name in this mib.|