Hi,
What you can do is examine the Activity log in the subscription where the deployment is failing and check which policies caused the failure. For example, in the Azure portal, you can open up the Activity log using link below:
https://portal.azure.com/#view/Microsoft_Azure_Monitoring/AzureMonitoringBrowseBlade/~/activityLog
Make sure the filter is set to correct subscription, time range, and then look at the Validate Deployment operations that failed. Click on one of the failed Validate Deployment entries, then select the JSON tab. Scroll down through the json until you see details of which policy caused the failure. That way you can take a look at the relevant policy definition(s) so you can figure out why they are blocking your deployment.
If the above was helpful please click Accept Answer.
Thanks.
-TP