Zoho Email, After Months Of Functioning, Won't Synch or Refresh

Zoho Email, After Months Of Functioning, Won't Synch or Refresh

I am a paid subscriber and have been using Zoho email for months and love it.  I use it on my PC, iPhone, iPad.

However, the last email I received was yesterday, which is not the case as I have checked my email via my email provider's web portal and I have many messages since.

Help...thanks!

Bobby