IIS Manager Error on Async Service Start
The error such as IIS Manager Error: The process cannot access the file because it is being used by another process. (Exception from HRESULT: 0x80070020) is as obvious in the description of the error in the message. This error can be faced when Async service for AX 2012 R3 is started in IIS as website, and it finds the particular port e.g. 443 or https in this case used by another process.
To find all the processes with port wise details, we can issue command : NETSTAT -ano and find out the PID for the process that is using port 443, then you can compare that PID with the process name in task manager.
Then the port of that process or ASync service can be changed, using binding settings in IIS.