Make sure that you're using the correct username and password.
Try resetting your password.
Check to see if your internet connection is working properly.
Try restarting your computer or mobile device.
If you're still having trouble, try logging in from a different device.
If you're using an emulator to play CarX Street Racing, make sure that you're using a reputable emulator and that it's up to date. You may also need to try logging in to the launcher with your Google account instead of your username and password.
After all this time, they still haven't fixed that? That's just sad. There's just no good excuse for ANY game, regardless of the developer, to require the intentional falsification of IP data to play.