SmarterMail is shown as not configured in Plesk: No process is on the other end of the pipe

Symptoms

• Unable to configure SmarterMail service via Tools & Settings > Server Components: after specifying the correct credentials no errors occur, however service is still shown as 'Not Configured'.
• In IIS > Sites > SmarterMail > Bindings SmarterMail is bound only to localhost.
• On attempt to access SmarterMail interface via http://127.0.0.1:9998 the error below appears:

  Bad Request - Invalid Hostname
  HTTP Error 400. The request hostname is invalid.

Cause

SmarterMail is not listening on 127.0.0.1.

Resolution

1. Log into the server via RDP.

   Note: if direct RDP access to the server is not possible, contact server administrator for further assistance.

2. Go to IIS > Sites > SmarterMail > Bindings.
3. Add the binding on port 9998 without specifying the Hostname to make it listen on all IP addresses including 127.0.0.1.
   
4. Go to IIS > Application Pools > SmarterMail > Advanced Settings:
5. Make sure that  Identity for SmarterMail application pool  is set to the NetworkService:
   

6. Execute the following command via the command line to open Windows Services Manager:

   C:> services.msc

7. Find out SmarterMail Service and restart it.
8. Configure SmarterMail once again under  Tools & Settings > Server Components