After an update from Microsoft, /secondary
Skype stopped working as mentioned in How can I run multiple Skype accounts in one computer?. I think they willfully want only one Skype should be working on a desktop.
The only one way I've found to run multiple Skype instances now is to just install the old classic Skype.
Is there any way to do it for new Skype?
Best Answer
After reading Ian's answer, I find it is a great solution to this my question. I am posting my own answer just to share my findings based on Ian's link as I faced difficulty on using above answer's path and settings.