Why am I unable to receive emails in IncrediMail a POP email client

Why am I unable to receive emails in IncrediMail a POP email client

Hi there,
   When I first signed up to zoho mail nearly 14 hours ago, I was able to send and receive emails just fine.  Now however, for the last 6 hours, I have not been able to receive my emails in IncrediMail, which is a POP email client.  All my settings for POP are correct, my username and password is correct...the only error message I'm getting in IncrediMail is err-service unavailable.  I have tried to remove the email address and add it again and again, but to no avail.  Please help as I'm pulling my hair out
Thank you,
Angela