Not receiving emails from non-zoho senders

Not receiving emails from non-zoho senders

I get emails from my colleagues when sending emails to each other on Zoho, but I'm not getting emails from other servers such as Hotmail, Gmail....etc. Also, my LinkedIn account is giving me this message: 

Emails aren't getting through to one of your email addresses. Please  update or confirm  your email.  More info

This means that they are not able to send me emails either.

I tried sending myself an email from my hotmail account and it bounces back saying this:

This is an automatically generated Delivery Status Notification.

Delivery to the following recipients failed.