I have a Zoho Mail app on my iPhone XR.  I had an update which did not load correctly so I logged out. When I went to log in again I received the following message 'Unable to Sign In - Refresh Token Has Been Reached.

I have tried to find out how to rectify it online but can't find anything definitive. I just need to know what to do to sort this out. I am a tech-beginner so plain language would be appreciated!!

Thanks very much

Kate