Login error when signing in outlook add-on but no errors encountered when using Zoho account in web browser

When trying to sign into outlook add-on, there is an error message asking for valid email address and password. I have attached a screenshot so you can gauge the problem. Have tried to unistall and re-install the add on but I think there is an issue and it needs to be immediately resolved as all other users in the company have also reported experiencing the same problem and it is seriously impeding work.

I have also emailed support but not had any response from them so far.

Thanks