As per the strict IRDAI guidelines, the insurance company/TPA cannot deny your request for cashless treatment unless there’s a valid reason to do so. Some of these reasons could be that:
The hospital you are seeking/planning to seek the treatment from is not part of preferred provider network.
The ailment you are seeking/planning to seek the treatment for is beyond the scope of coverage of your insurance policy.
The information mentioned in the request form is incomplete or insufficient.
You have already used the entire sum assured for that year.