Email functionality- invoices module not working , etc..... – Zoho CRM - Sales & Marketing Review

Since the last update 2 w ago, when trying to send an email to a contact thru “invoices”, module will not automatically populate the contact’s email address (having to select manually the correct email is very difficult when you over 3k contacts with multiple emails with one address already set as default). App is constantly throwing an error message of some kind (I’ve sent the error log so many times that I’ve lost count) App is not populating field which already has a predetermined value (this has always worked fine until 2w or so ago)
Review by CheJua on Zoho CRM - Sales & Marketing.