We am using zohomail from quite some time now and we are happy using the solution and we recommend it to anyone who ask us for email platform. 

We have seen a strange error to some of the email receipts {Working business emails} emails are never delivered, also when some users are sending mail to us we dont get it, same time they receive our mails. 

Pl suggest how to fix it, because of this we may be losing lot of business. 

Your help is highly appreciated