A visitor says the form did nothing. The form plugin shows no entry. The inbox is empty, but there is one message in the spam folder from a different address. The access log shows POST requests to the form endpoint from a handful of IPs. Those are separate failures. Changing the form settings before separating them usually removes the evidence you need.

Collect the basics before you touch settings: the exact submission time with timezone, the recipient address, the page URL, and whether the form plugin shows an entry. Ask the recipient to forward the message as an attachment if they can.…