Not receiving all emails

Not receiving all emails

Hi,

I have newly setup my account and found not all mails have been received and I'm being notified. Even from the same sender, I would receive some and not receive some.
 
Also, I have setup both zoho email accounts in my Iphone mail, but I found all of the mails being received in my zoho accounts have been linked to one of the email I received in one of my gmail account. This is so weird that I have never experienced before. Can anyone help?  Thanks.