Probe Exception: 'System.Net.Sockets.SocketException (0x80004005): No connection could be made because the target machine actively refused it 127.0.0.1:587 on Exchange Servers

You get following events in the Managed Availability Logs on Exchange 2013/2016.

Log Name: Microsoft-Exchange-ManagedAvailability/Monitoring
Source: Microsoft-Exchange-ManagedAvailability
Date:  
Event ID: 4
Task Category: Monitoring
Level: Error
Keywords:
User: SYSTEM
Computer:  
Description:
The client submission probe failed 3 times over 15 minutes.
No connection could be made because the target machine actively refused it 127.0.0.1:587
Probe Exception: 'System.Net.Sockets.SocketException (0x80004005): No connection could be made because the target machine actively refused it 127.0.0.1:587
at System.Net.Sockets.TcpClient..ctor(String hostname, Int32 port)
at Microsoft.Forefront.Monitoring.ActiveMonitoring.Smtp.Probes.SimpleSmtpClient.Connect(String server, Int32 port, Boolean disconnectIfConnected)
at Microsoft.Forefront.Monitoring.ActiveMonitoring.Smtp.Probes.SmtpConnectionProbe.MeasureLatency(String reason, ActionWithReturn`1 cmd)
at Microsoft.Forefront.Monitoring.ActiveMonitoring.Smtp.Probes.SmtpConnectionProbe.MeasureLatency(String reason, ActionWithReturn`1 cmd, ConnectionLostPoint connectionLostPoint)
at Microsoft.Forefront.Monitoring.ActiveMonitoring.Smtp.Probes.SmtpConnectionProbe.TestConnection()
at Microsoft.Forefront.Monitoring.ActiveMonitoring.Smtp.Probes.SmtpConnectionProbe.DoWork(CancellationToken cancellationToken)
at Microsoft.Office.Datacenter.WorkerTaskFramework.WorkItem.Execute(CancellationToken joinedToken)
at Microsoft.Office.Datacenter.WorkerTaskFramework.WorkItem.<>c__DisplayClass2.<StartExecuting>b__0()
at System.Threading.Tasks.Task.Execute()'
Failure Context: 'No connection could be made because the target machine actively refused it 127.0.0.1:587'
Execution Context: ''
Probe Result Name: 'OnPremisesSmtpClientSubmission'
Probe Result Type: 'Failed'
Monitor Total Value: '3'
Monitor Total Sample Count: '3'
Monitor Total Failed Count: '0'
Monitor Poisoned Count: '0'
Monitor First Alert Observed Time:

It happens if "Client Frontend <server>" receive connector does not have (All Available IPv4) in the "Network adapter bindings" instead it is set as server local IP address.

So you can change it to (All Available IPv4) on port 587 then you should be able to telnet 127.0.0.1 on 587 locally on the server.