This can be happening because the browser takes a little more time to recognize your status after you make or receive a call.
As you can see, while you are on a call, your agent status turns orange. It meas you appear as busy, and you will not receive any other call.
If you stay as busy even after you finished the call, we'd recommend you to restart the browser, and if you still appear as busy you can set yourself online.
2. You just need to click on your username, and you will find the Set to Online option.
This should get you back online and you should be able to continue receiving calls from your customers😄