Why the delay between Zoho Mail and Zoho CRM on inbound email alerts?

Why the delay between Zoho Mail and Zoho CRM on inbound email alerts?

So when I have my email set to be received in Zoho Mail and Zoho CRM. I will receive an email and receive the alert from Zoho Mail, it will be received and Zoho CRM too...but here's is the problem. I do not get an alert on the top of my screen for some time. The delays are significant and make working in CRM exclusively a hassle.

Paul