Hello Karan,
As it is very common cause of not finding any condition record is an incorrect data format in the rule determination. Let us say if a Customer is used as a Characteristic then leading zeroes have to be considered if any etc. Please make sure Characteristic values from Sales Order has corresponding rule defined and found in Rule Determination (/SAPCND/AO13). Please verify the data format etc.
Hope this will help.
Thank you
Satish Waghmare