I was always able to send my emails normally but in the last two weeks I noticed that my emails are not being received by one company. Before this two weeks everything was ok we were sending messages and emails without a problem, but then they stopped receiving my email. I tried adding other email addresses to see if other users can get the mail and indeed they do but the most important company is not receiving it. 

We already asked to see the Spam and Not wanted email, but it was not there either. Zoho is not giving any warning and all mails to other users are being delivered without problem. Can you check on this?