Hi iq,
What is the URL that is showing in the address bar when you try to save the Email options? Can you make changes in any of the other options tabs in the plugin? Were you ever able to make changes to the emails tab? If so, when did it stop working? Perhaps it’s a conflict with something else. What happens if you temporarily deactivate all other plugins? Does it work then? What about if you switch to a default WordPress theme?
Also, do you happen to be using a Windows server, or Windows IIS server, as opposed to a Linux server? While WordPress installs, and PHP sites for that matter, can and do work just fine on Windows servers, they are native to Linux servers. As such, there are often a few tweaks necessary to get it working the way you want on a Windows server. For example, if you’re getting the above error, it often means that you haven’t specified a default document. Have a look at the following links for information about this: https://support.microsoft.com/en-ca/help/942062/-http-error-403.14—forbidden-error-when-you-open-an-iis-7.0-webpage and http://www.riptidehosting.com/blog/wordpress-error-windows-server-http-error-403-14-forbiden/. It’s possible that you’d have to do further research and tweaks, beyond the aforementioned, to get everything working correctly on the Windows server.
