SCOM cannot discover Linux or UNIX based host with "Unspecified failure"

Scenario:
SCOM cannot discover Linux or UNIX based host and reports error:

Unexpected DiscoveryResult.ErrorData type. Please file bug report.
ErrorData: Microsoft.SystemCenter.CrossPlatform.ClientLibrary.Common.SDKAbstraction.TaskInvocationException
Task invocation failed with error code -2130771857. Error message was: 0x80FF006F
at System.Activities.WorkflowApplication.Invoke(Activity activity, IDictionary`2 inputs, WorkflowInstanceExtensionManager extensions, TimeSpan timeout)
at System.Activities.WorkflowInvoker.Invoke(Activity workflow, IDictionary`2 inputs, TimeSpan timeout, WorkflowInstanceExtensionManager extensions)
at Microsoft.SystemCenter.CrossPlatform.ClientActions.DefaultDiscovery.InvokeWorkflow(IManagedObject managementActionPoint, DiscoveryTargetEndpoint criteria, IInstallableAgents installableAgents)

Resolution:
There are 2 possible reasons of this problem:

• "WS-Management Action Account" profile can contain "Run As Account" with wrong scope something like "All targeted objects"
• Some users reported they've used special characters like "&" in account password used for Linux/UNIX host discovery

References:

• SCOM 2012 Troubleshooting: UNIX/Linux Agent Discovery
• SCOM 2012, WSMan, and Unix/Linux Computer Discovery
• SCOM 2012 R2: Manually installing and troubleshooting Linux/UNIX Agents
• Windows Remote Management Authentication for Remote Connections