Hi Diya,

If you are a Commerce graduate, you're definitely eligible for CAT given you meet all other eligibility criteria. There might have been some mistake or network issue which resulted you not being able to complete your form.

Follow this link as it gives you a step by step guide how to fill your CAT form. https://bschool.careers360.com/articles/how-to-fill-cat-application-form-step-step-guide

Feel free to address any other issue you might face.