No, your IEC application cannot be denied before completing your biometrics measurements. Canada visa officers only review your application profile after receiving your biometrics. Once they have received your biometrics, it is possible for your application to be denied. But not during the biometrics process.
IMPORTANT: Your permit application will be denied if you do not complete your biometrics — this step is mandatory.
You have 30 days after receiving your biometrics instruction letter to complete them. Make sure you do so within that time frame to avoid your application being denied.