I applied for OFS at Market rate, but I still did not get allotment?

Non allotment can be due to any of the below reasons:

1. The price at which you had applied was less than the clearing price of the OFS in that category could result in non-allotment. 
2. https://www.nseindia.com/live_market/content/live_watch/offer_sale/ofs_sale.htm
3. When you apply at market price, application is made at the allotment price of the general category. If the allotment price of the retail category is higher than that of the general category, you will not get any allotment.
4. If the bid value exceeds 2 lacs in retail category, you will not be allotted shares. This can be the case you have applied with multiple brokers.
5. Application in both, retail and general category can result in non-allotment.