Incoming Emails Not Showing Up in Zoho Inbox

Incoming Emails Not Showing Up in Zoho Inbox

Hi - I have my Zoho email account set up to forward a copy of all incoming emails to a secondary Gmail address, whilst retaining the original email in the Zoho inbox. However, all my incoming emails are currently not showing up in my Zoho inbox, so I'm unable to reply to anything.

I have checked the inbox of the Gmail account and incoming emails have been successfully forwarded there, and when I check the Zoho Email Logs in the 'Troubleshooting' section of the Zoho control panel, I'm able to see that incoming emails have been successfully received by the Zoho server - they're just not showing up in the inbox folder. 

Anyone know what the problem might be or how to fix? Not great to be unable to reply to any business emails until it's sorted...!