I have an old macbook air version 10.6 and the application used to work few years ago but not anymore now.

how to fix the problem can anyone help plzzz

It's gonna be stupidly obvious advice but what about upgrading your mac?

Upgrading macros can solve many issues, but unfortunately, it's not a universal approach. Some difficulties cannot be solved this way. And the TS's problem (I bet) isn't related to this. By the way, recently, I tried to deal with CPU usage issues. I thought a newer version would do a thing, but it didn't. I found on this page https://setapp.com/how-to/check-cpu-usage-on-mac what I should do and pay attention to.