The maximum duration for completing a program offered by IGNOU is usually specified by the university. If you have exceeded this duration and have not been able to complete the program, you will not be eligible to appear for the term-end examination.
However, if you feel that you have genuine reasons for not being able to complete the program within the specified duration, you may request an extension. The request for extension has to be submitted to the concerned Regional Center along with the required fees and necessary documents. The Regional Center will review your request and may grant an extension of duration, if found to be genuine.
In any case, you are advised to contact the IGNOU Regional Center or Student Service Center for clarification on your eligibility to appear for the term-end examination.