I obviously circumvented the problem but putting this out here for the Formidable Forms developers to know. I was being prevented from joining this forum by FF's spam protection measure which showed the error "Your entry appears to be spam!" (attached screenshot). This seems to be caused by Akismet which is recommended by and integrated into FF as described here. They seem to be aware of the issue and suggest it's because "you might have an email address or URL that is getting flagged". However, I was logged into my FF account on the same browser using the same email address I entered into the form, and was not providing any URL at all. I also easily "fooled" Akismet by submitting the form in a private tab using the same email address and other info. Thought to let the devs and the FF users know that it's is not a very smart protection method (and the issue has been around for years). I hope FF considers adopting other solutions.