Cutomer not replicated to ECC to CRM

Hi Friends,

I am facing the below two issues, please help me on them.

Issue1: The customer which is created in ECC is not getting replicated to CRM and even BDoc is not available for the same and other middleware settings are correct.

Issue2: The Customer which is created in CRM is not getting replicated to ECC and even BDoc is not available for the same and other middleware settings are correct.

In both cases, it's happening some customers only not for all.

Please help me on this issue.

Thanks and Regards,
Venkat