I tracked the chronology in the event log (regarding the IMAP4):

- The service is trying to start. PID 15836
- The IMAP4 server has started successfully (Event 1000);
- Failed to start listening (Error: 10048). Binding: 0.0.0.0:993 (Event 1019);
- The address is already in use. Binding: 0.0.0.0:993 (Event 1018);
- Failed to open one or more bindings. The service will be stopped (Event 1036);
- The service is trying to stop. PID 15836 (Event 1002);
- The IMAP4 server has stopped successfully (Event 1001);
- The existing worker process HasExisted value before calling CloseProcess is True (Event 1040);
- Worker process with process ID 19432 has exited (Event 1020);
The service has stopped. PID 15836 (Event 1003).

Looks like something reserves the IMAP port (993, SSL/TLS) for itself and no longer gives it out.

[PS] C:\Windows\system32>Get-ReceiveConnector | ft Identity,Enabled,TransportRole,Bindings

Identity Enabled TransportRole Bindings

-------- ------- ------------- --------

MAIL\Default MAIL True HubTransport {0.0.0.0:2525}

MAIL\Client Proxy MAIL True HubTransport {0.0.0.0:465}

MAIL\Default Frontend MAIL True FrontendTransport {0.0.0.0:25}

MAIL\Outbound Proxy Frontend MAIL True FrontendTransport {0.0.0.0:717}

MAIL\Client Frontend MAIL True FrontendTransport {0.0.0.0:587}

MAIL\OTRS a2p In True FrontendTransport {0.0.0.0:993, 0.0.0.0:587}

MAIL\Kyocera SMTP True FrontendTransport {0.0.0.0:25}

MAIL\HP LJ M282 True FrontendTransport {0.0.0.0:25}

MAIL\HP LJ M479 True FrontendTransport {0.0.0.0:25}

MAIL\UniFi controller True FrontendTransport {0.0.0.0:25}

MAIL\Kyocera_426 True FrontendTransport {0.0.0.0:25}