Your options now
What you can do next will depend on whether you applied inside or outside the UK.
Outside the UK
You can make a new immigration application if QMUL is happy to issue a new CAS, or you can submit an application for Administrative Review. You cannot do both at the same time, only one or the other.
Inside the UK
If your most recent immigration permission has not yet expired, and QMUL is happy to issue a new CAS, you can make a new immigration application. Alternatively, you can submit an application for Administrative Review instead (but note the warning above about overstaying).
If your immigration permission has now expired, you can make a new immigration application, but only from your home country, not in the UK. You can also submit an application for Administrative Review.
Law, regulations and policies can change quickly. The information on our website is given in good faith and has been carefully checked but QMUL cannot accept responsibility for any errors or omissions. QMUL is not responsible for the content or reliability of the linked websites which are provided for further information.