The number of resit attempts you have depends on when you started your course. Information about this can be found here.
If you fail a resit in August, you'll need to check whether or not this module is compulsory. If you've failed a compulsory module, this is likely to be your final attempt and you may not be able to continue on your course. You do have the choice to appeal this result and you can come to LUU Advice for support with this.
If you sat an August resit as a first attempt because you had mitigating circumstances, you may be able to have a further attempt to resit at the next available time - i.e. in January or May of the next academic year. This will affect the next year of your degree and you will usually have to retake the exam as an external student.
If you fail a non-compulsory module you can still pass the year as long as you have enough credits in total. You might be able to take your final resit with your other exams next year. To check if you can do this, just speak to your School.
You can only progress to the next year of your course if you have sufficient credits. You can seek further advice from your School.