[Plugin: Contact Form 7] EVERY message causes an orange-border spam message

Hi, I have read through and see that the orange-bordered “failed to send” message is an Akismet warning.

The problem is, every single message I or anyone else tries to send generates this message. I am using real email addresses (my own) and contents like “test.” or “this is my message.”

The email sent fine when I first installed this one week ago. It suddenly stopped working. I have not installed a new plugin I can think of that might conflict.

Also, Akismet is not showing any spam reports to suggest that it is blocking submissions. My spam count there has been 0 for weeks.

Is there any other reason that this orange-bordered “Failed to send your message. Please try later or contact administrator by other way” might be triggered? Thanks.