Not receiving certain email

Unable to receive email from select non-Cox email addresses.  However, am able to receive the very same messages using my gmail email address.  Was able to subsequently forward those same messages (i.e. the ones sent to my gmail address) to my cox emali address with no problem.  Because of this, I am able to see the address of the originator of the messages in question.  One such example is:

    noreply@gmail.amazon.jobs

NOTE: 

• I am using Microsoft Outlook as my email software.
• Checked all other non-Inbox folders to see if messages are being stored there instead (including SPAM/Junk email folder).  No sign of any such messages. 

I am really concerned as to how many other such messages sent to my cox email I am not receiving, nor being notified.

If it would help, there is another site that I am trying to get info from in the same fashion as the gmail.amazon.jobs message listed above.  If it would help, I could have them attempt to re-send their message if someone would like to 'sniff' the message traffic.   Please advise.