I just found this out myself. (I am new to Blocs.). You will get an error until you Export and then upload to your webserver.
I am curious why the content of the fields are deleted upon success or failure though. It's especially awful in the case of a failure because the failure means "try again later." But the message you just typed will have been deleted!
If this functionality could be corrected, it would be helpful. Why? Because when such email forms fail on other sites, I then select my message text, copy it, and then use that same text again later. Blocs deletes that text before you have a chance to save it!
Norm, if this is possible to improve, that would be great.
How can I change the "Not a valid email address" text? I design websites in the Japanese language. People in Japan won't understand that English error text, so I want to translate it to Japanese. How can I do that?
Another language related problem...
In Blocs, I want to type Japanese into the form's "Subject" field. Blocs allows me to do that, but then when I export and upload and Submit, the email that arrives has its Subject line garbled. It is therefore clear that Blocs is not encoding the Subject line properly. A bug?