Hi Jitesh,
you say you 'migrated' your PKI. how did you migrate or did you build new CA(s)?
you may want to look into the CA properties (from memory it is on the extensions tab) and review the configuration for the CRL locations. Specifically check publish to and include in certificates settings.
If those are all correct then check in the CA's logs. There will be an event logged if the CA is having trouble publishing a CRL or delta to a given location and will give a reason. The reason will lead you to your next step.
If the CRL publish configuration is not correct in the CA's properties then there won't be errors in the event logs; as the CA won't try.
HTH
Regards,