You must use auto-captcha service to solve it as it says in full error (hover the mouse over the error message and you will see it).
Setup auto-captcha service in "CONFIG" -> "Captcha" tab (Anti-Captcha recommended) and it will be fine.
If you're already using auto-captcha service then preview the error in "Captcha/Q" tab -> "Auto-Captcha" errors.
If you're using Anti-Captcha you will probably see that your bid is too low. Login in Anti-Captcha website and increase your bid in their API settings (set it to at least 4$).