Overview
Fax lines are showing as "Not initialized: 18" on the monitor after migrating your FaxMaker server from a physical to a virtual server.
You may have tested it and the modem's COM port correctly responds to AT commands.
Solution
This has been observed when multiple lines are enabled in the Lines/Devices, but not all of them are actually in use.
In the FaxMaker Configuration Tool, disable all the lines that are not going to be used for sending or receiving faxes:
Also, check the Windows Task Manager and make sure there are not any hanging instances of the FaxMaker installer. If you find any, just terminate them.
Testing
Restart the FaxMaker services and check the line status in the monitor.
For additional troubleshooting, check the Lines Not Initialized in the GFI FaxMaker Monitor article.