Unable to login in Zoho Mail on Android

One of our user account suddenly is unable to login to her Zoho Mail account thru Android Zoho Mail app. It keeps telling her to check with admin if one of the features (i.e. calendar, crm, etc) has been disabled, but I checked the features and all are enabled.

She can login to desktop thru a web browser but not on Android Zoho Mail app.

Please help.