Hello,

We are facing delivery errors from several domains. some of those business domains send a failure notice and other don't send anything yet our emails are not delivered at all.

Sample of those domain are: 

-vodafone.com.eg : and it returns failure report

-makaryconsulting.com: and it return failure report

-tatelecom.com: doesn't return anything at all and emails are not received

-hindawi.com: doesn't return anything at all also