RHV: hosts are not responding, seeing 'Too many tasks' error

Issue

• Host is not responding, following error is shown in the engine:

Unable to RefreshCapabilities: VDSNetworkException: VDSGenericException: VDSNetworkException: Not enough resources: {'reason': 'Too many tasks', 'resource': 'jsonrpc', 'current_tasks': 80}

• Supervdsm is not generating logs in the hypervisor.
• Supervdsm is not responding to network_caps() from VDSM
• VDSM has several tasks blocked on getCapabilities()