I want to run tests in parallel in Appium, but my tests are not running correctly

Hello Guys. I work as a test automation engineer in a company in Turkey. Currently, we have 1000 test cases. I have written these using Appium, Cucumber, and TestNG. I want to run the tests in parallel on my local machine to reduce test execution time. However, there seems to be an issue with my configuration as the tests are not running correctly in parallel. They run successfully when I run them individually, but I encounter errors when running them in parallel. Would you be willing to assist me if I share my code with you? I really need help with this.