WebApp dies immediately on macOS Catalina

I recently updated my mac to Catalina (10.15.3) and I am using Xojo 2019.3… Previous projects are not launching, without notice.

I run the application, it then compiles and informs that it is launching the app, but after second or two it returns to the IDE without actually launching the app.

If I start a brand new web object it will launch properly.

I have removed all plugins (I only have MBS), and yet the same result.

This is also happen with the example projects that come with Xojo.

Please help me. I am stunned with this problem.

Wrong port?
Crash report?

I can’t believe it. Out of answers so I decided to restart my computer… problem solved.

There must have been some remanent software in the background that was troubling my computer without realizing it.

Sorry to have bothered you with something so elementary.

Dying immediately is usually caused by the debug port being in use.