can't open cobalt 20 on my mac


this evening i downloaded cobalt 20 and I installed it on my MacBook Pro (10.10.5)

the install finished properly but when I run it, the application doesn't want to run. the cobalt icon's bounce on my dock and stopped after 1 minute (more or less).

before that I had cobalt and all work good. i deleted this version before install the new one


thanks for your help