My acc is sending e-mails but not receiving any!

My acc is sending e-mails but not receiving any!

I sent a mail from my gmail to zoho account and it was not delivered. When I sent a mail from zoho to my gmail, it was delivered. However when I forwarded the same mail from gmail to zoho, nothing happened, the mail was not delivered to zoho. 

It seems we can send mails from zoho to others but they cannot send mails to my zoho account. 

What should I do to solve this issue?