Hello, I have the same problem. I red your dialog but it wasn't very helpful for me... So I have the same situation: Users login and create accounts via third party social application which means accounts are without email. When users try comment they get the same error: "some of fields value is invalid"
I red in your forum that its the problem of Wordpress. Well not exactly, my themes native commenting system allows me to comment without email, or captcha so it works fine, but I prefer design and functionality of wpDiscuz more so I really hope someone could help me to fix it.
Please try to uncheck the Required checkbox of the Email field in Comment Form setting page.
Yes, It is unchecked but still doesn't work.
I have the same problem. Any solution?