I cannot ready my emails on a PC or Mac, I can log in and see them on the left hand side but when clicking on them I get the message "Oops! An error occured". 

They work on the app on my iPhone however.

I feel like this is a Zoho issue that needs looking into. I've logged in on Chrome and Edge, I've deleted cache and tried on multiple devices, the only that will work is the app on my iPhone. 

Has anyone else had similar or can offer any advice?

Thanks,

Andy