App doesn't work.

The download page for Mac explains why they haven't made a current version available:

NOTES:

• Code::Blocks 20.03 for Mac is currently not available due to issues caused by Apple hardening their install packages and lack of Mac developers. We could use an extra Mac developer to work on these issues.
• The provided download contains an Application Bundle (for the i386 architecture) built for Mac OS X 10.6 (and later), bundling most Code::Blocks plugins.

There is a very old version available, and it is not surprising that it almost certainly does not work.

There are, however, other development environments you can use in a Mac to program in C++ - starting with XCode, the Apple development platform.

https://www.codeblocks.org/features/

Highlights:

• Open Source! GPLv3, no hidden costs.
• Cross-platform. Runs on Linux, Mac, Windows (uses wxWidgets).
• Written in C++. No interpreted languages or proprietary libs needed.
• Extensible through plugins