Hello,
When a test closes a browser it takes some time to gracefully finish its process.
When TC starts the second test right after the first test, the process of a "previous browser" may still exist as it didn't have enough time to finish.
To run all tests in succession, you may
add some delay at the end of each test, after the instructions that close the browser
check for any running browsers and close them in the beginning of each test, as per Murugan S and as described in Checking if Browser Is Running
The second variant is preferable, as it can close all running browsers, rather than just one we used in a test.
