Smartthing simulator IDE not working

I follow the instructions and want to get the smartapp run in the simulator IDE, but nothing changed in the simulator after I clicked the play button of virtuel switches. NO logging info printed out and no button turned green.
https://docs.smartthings.com/en/latest/getting-started/first-smartapp.html

I tested on Firefox and Chrome. Does anyone has an idea?

There is a similar question posted in 2016.

The simulator in the IDE worked sporadically. I played with it a bit in 2016 and never really found it useful. My impression back then was the author of the simulator had already left the company, and that no one was interested in maintaining it.

And with them getting rid of the whole IDE soon (along with Groovy support), I doubt this will ever be addressed.

I’ve only been using SmartThings two or three years, but by then the general feeling in the community was not to bother with the Simulator, and ST staff didn’t seem minded to dispute that view. It was always considered better to use the simulated devices if using the real thing wasn’t practical.

Thanks for the reply, Have a good day!

Thanks a lot and Merry Christmas! Since I could not verify in the simulator IDE, is there any way for me to test with simulated devices?

In the question posted in 2016, I found:

Once you “publish for me” a DTH or SmartApp you can: a. Instantiate Devices using the IDE Add Device, select any unique name & ID, b. Install the SmartApp from the My SmartApps at bottom of Marketplace tab in the App.

It seems the smartthing app in 2020 canceled this part.

Anyway, thanks so much for your help!

I am also getting similar issue using the simulator, Is there any solution? Thanks!